Quarterly report pursuant to Section 13 or 15(d)

Available-for-sale Securities Classified by Rate Type (Details)

v3.19.1
Available-for-sale Securities Classified by Rate Type (Details) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Adjustable Rate $ 3,275,799 $ 3,494,244
Fixed Rate 21,801,911 22,058,360
Available-for-sale securities, at fair value 25,077,710 25,552,604
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Adjustable Rate 17,669 19,073
Fixed Rate 21,515,529 21,665,960
Available-for-sale securities, at fair value 21,533,198 21,685,033
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Adjustable Rate 3,258,130 3,475,171
Fixed Rate 286,382 392,400
Available-for-sale securities, at fair value $ 3,544,512 $ 3,867,571