Federal Home Loan Bank Advances (Summary Of Advances Payable To The Federal Home Loan Bank) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Total Outstanding
Within 1 year	$ 2,275,000	$ 1,550,000
After 1 but within 2 years	145,934	0
After 2 but within 3 years	500	145,934
After 3 but within 4 years	200,000	500
After 4 but within 5 years	78,026	200,000
After 5 years	159,934	155,926
Federal Home Loan Bank advances	2,859,394	2,052,360
Unamortized premiums	37	61
Federal Home Loan Bank advances	$ 2,859,431	$ 2,052,421
Weighted- Average Contractual Coupon Rate
Within 1 year	0.23%	0.25%
After 1 but within 2 years	1.80%	0.00%
After 2 but within 3 years	5.66%	1.80%
After 3 but within 4 years	1.36%	5.66%
After 4 but within 5 years	1.95%	1.36%
After 5 years	1.27%	1.25%
Weighted- Average Contractual Coupon Rate	0.50%	0.54%