Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
Available-for-Sale Securities, Weighted Average Life Classifications (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value $ 21,882  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 105,093  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 822,357  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 11,478,797  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 700,728  
Available-for-sale Securities 13,128,857 $ 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 1,198  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 48,595  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 614,633  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 10,532,188  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 29,860  
Available-for-sale Securities 11,226,474 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 20,684  
Available-for-sale Securities, Debt Maturities, Year Two Through Three, Fair Value 56,498  
Available-for-sale Securities, Debt Maturities, Year Four Through Five, Fair Value 207,724  
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value 946,609  
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 670,868  
Available-for-sale Securities $ 1,902,383 $ 1,852,430