Quarterly report pursuant to Section 13 or 15(d)

Available-for-Sale Securities, Weighted Average Life Classifications (Details)

v3.4.0.3
Available-for-Sale Securities, Weighted Average Life Classifications (Details) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value $ 81,322  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 109,345  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 2,899,024  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 6,088,745  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 406,018  
Available-for-sale Securities 9,584,454 $ 7,825,320
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value 1,435  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 55,448  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 2,609,341  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 5,337,237  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 5,635  
Available-for-sale Securities 8,009,096 5,972,890
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value 79,887  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 53,897  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 289,683  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 751,508  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 400,383  
Available-for-sale Securities $ 1,575,358 $ 1,852,430