Annual report pursuant to Section 13 and 15(d)

Schedule of Available-for-sale Securities Reconciliation, Non-Agency Unamortized Net Discount and Designated Credit Reserves (Details)

v3.8.0.1
Schedule of Available-for-sale Securities Reconciliation, Non-Agency Unamortized Net Discount and Designated Credit Reserves (Details) - Mortgage-backed Securities, Issued by Private Enterprises [Member] - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Available-for-sale Securities, Designated Credit Reserve [Member]    
Available-for-sale Securities, Unamortized Discount [Roll Forward]    
Total discount/premium on available-for-sale securities, beginning balance $ (367,437) $ (409,077)
Acquisitions (373,051) (70,108)
Accretion of net discount 0 0
Realized credit losses 17,539 1,969
Reclassification adjustment for other-than-temporary impairments (789) 914
Transfers from (to) 66,537 74,972
Sales, calls, other 3,588 33,893
Total discount/premium on available-for-sale securities, ending balance (653,613) (367,437)
Available-for-sale Securities, Net Unamortized Discount/Premium[Member]    
Available-for-sale Securities, Unamortized Discount [Roll Forward]    
Total discount/premium on available-for-sale securities, beginning balance (623,440) (477,176)
Acquisitions (57,732) (189,754)
Accretion of net discount 88,037 69,542
Realized credit losses 0 0
Reclassification adjustment for other-than-temporary impairments 0 0
Transfers from (to) (66,537) (74,972)
Sales, calls, other 52,063 48,920
Total discount/premium on available-for-sale securities, ending balance (607,609) (623,440)
Available-for-sale Securities, Total Discount/Premium [Member]    
Available-for-sale Securities, Unamortized Discount [Roll Forward]    
Total discount/premium on available-for-sale securities, beginning balance (990,877) (886,253)
Acquisitions (430,783) (259,862)
Accretion of net discount 88,037 69,542
Realized credit losses 17,539 1,969
Reclassification adjustment for other-than-temporary impairments (789) 914
Transfers from (to) 0 0
Sales, calls, other 55,651 82,813
Total discount/premium on available-for-sale securities, ending balance $ (1,261,222) $ (990,877)