Quarterly report pursuant to Section 13 or 15(d)

Other Financing Lines of Credit - Summary Of Components of other financing lines of credit (Parenthetical) (Detail)

v3.21.2
Other Financing Lines of Credit - Summary Of Components of other financing lines of credit (Parenthetical) (Detail) - USD ($)
$ in Thousands
 6 Months Ended
Jun. 30, 2021
Feb. 28, 2021
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 6,066,690  
Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 3,688,951  
Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 1,613,715  
Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 764,024  
March 2026 $150M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 150,000  
March 2022 $200M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
March 2022 $225M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 225,000  
March 2022 $300M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 300,000  
February 2022 $300M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 300,000  
May 2022 $200M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
October 2021 $250M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 250,000  
August 2021 $200M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
August 2021 $300M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 300,000  
July 2021 $200M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
April 2022 $250M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 250,000  
April 2022 $250M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 250,000  
May 2022 $350M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 350,000  
February 2021 $50M Facility    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity   $ 50,000
February 2021 $50M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 50,000  
Floor insterst rate, Line of credit facility 5.00%  
October 2021 $200M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 200,000  
April 2022 $50M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 50,000  
Floor insterst rate, Line of credit facility 6.00%  
August 2021 $50M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 50,000  
October 2021 $400M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 400,000  
December 2021 $100M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 100,000  
March 2022 $100M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 100,000  
April 2022 $52.5M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 52,500  
April 2022 $45M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 45,000  
Debt instrument, interest rate stated percentage 9.00%  
February 2024 $90M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 90,000  
$2M Securities Repo Line | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 2,000  
April 2023 $145M Facility | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 145,000  
February 2022 $150M Facility | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 150,000  
August 2022 $75M | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 75,000  
August 2022 $75M | Commercial Lines Of Credit [Member] | Maximum [Member]    
Line of Credit Facility [Line Items]    
Debt instrument, interest rate stated percentage 3.25%  
August 2022 $75M | Commercial Lines Of Credit [Member] | Minimum [Member]    
Line of Credit Facility [Line Items]    
Debt instrument, interest rate stated percentage 2.50%  
June 2023 $300M Facility | Mortgage Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 300,000  
$200M Repo Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
$1.2M Repo Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 1,215  
June 2022 $75M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 75,000  
June 2022 $200M Facility | Reverse Line Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 200,000  
August 2021 $25M Facility | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 25,000  
Debt instrument, interest rate stated percentage 10.00%  
$4M Securities Repo Line | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 4,024  
November 2023 $65M Facility | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity 65,000  
September 2022 $150M Facility | Commercial Lines Of Credit [Member]    
Line of Credit Facility [Line Items]    
Line of credit facility, Maximum borrowing capacity $ 150,000