Annual report pursuant to Section 13 and 15(d)

Variable Interest Entities (Details)

v3.8.0.1
Variable Interest Entities (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Variable Interest Entity [Line Items]      
Assets of consolidated Variable Interest Entities $ 0 $ 3,290,245  
Liabilities of consolidated Variable Interest Entities 0 3,058,278  
Loans Held-for-Investment, Residential Mortgages [Member]      
Variable Interest Entity [Line Items]      
Assets of consolidated Variable Interest Entities 0 3,271,317  
Assets of nonconsolidated Variable Interest Entities 2,984,507 0 $ 0
Accrued Income Receivable [Member]      
Variable Interest Entity [Line Items]      
Assets of consolidated Variable Interest Entities 0 18,928  
Assets of nonconsolidated Variable Interest Entities 15,386 0 $ 0
Assets, Total [Member]      
Variable Interest Entity [Line Items]      
Assets of consolidated Variable Interest Entities 0 3,290,245  
Collateralized Borrowings [Member]      
Variable Interest Entity [Line Items]      
Liabilities of consolidated Variable Interest Entities 0 3,037,196  
Accrued Liabilities [Member]      
Variable Interest Entity [Line Items]      
Liabilities of consolidated Variable Interest Entities 0 8,708  
Other Liabilities [Member]      
Variable Interest Entity [Line Items]      
Liabilities of consolidated Variable Interest Entities 0 12,374  
Liabilities, Total [Member]      
Variable Interest Entity [Line Items]      
Liabilities of consolidated Variable Interest Entities 0 3,058,278  
Mortgage-backed Securities, Issued by Private Enterprises [Member]      
Variable Interest Entity [Line Items]      
Assets of nonconsolidated Variable Interest Entities 2,982,094 1,889,696  
Maximum exposure to loss of nonconsolidated Variable Interest Entities $ 2,982,094 $ 1,902,384