Contractual Maturities of Outstanding Federal Home Loan Bank Advances (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amount
2016	$ 2,500,000	$ 2,300,000
Total FHLB advances	13,463,800	$ 10,183,132
Contractual Maturity
Amount
2016	3,290,300
2017	1,550,000
2018	4,423,500
2019	2,700,000
2020	1,500,000
Total FHLB advances	$ 13,463,800
Weighted Average Interest Rate
2016	0.55%
2017	1.29%
2018	1.50%
2019	1.74%
2020	1.93%
Total FHLB advances	1.34%