Investment Securities (Summary Of Debt Securities By Contractual Maturity) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]
Available for Sale, Amortized Cost - Due in one year or less	$ 325
Available for Sale, Amortized Cost - Due after one year through five years	101,544
Available for Sale, Amortized Cost - Due after five through ten years	213,552
Available for Sale, Amortized Cost - Due after ten years	2,793,177
Available for Sale, Amortized Cost - Total debt securities	3,108,598
Available for Sale, Fair Value - Due in one year or less	325
Available for Sale, Fair Value - Due after one year through five years	105,492
Available for Sale, Fair Value - Due after five through ten years	214,124
Available for Sale, Fair Value - Due after ten years	2,783,406
Available for Sale, Fair Value - Total debt securities	3,103,347
Held to Maturity, Amortized Cost - Due in one year or less	90
Held to Maturity, Amortized Cost - Due after one year through five years	84,923
Held to Maturity, Amortized Cost - Due after five through ten years	103,728
Held to Maturity, Amortized Cost - Due after ten years	3,169,980
Held to Maturity, Amortized Cost - Total debt securities	3,358,721	3,107,529
Held to Maturity, Fair Value - Due in one year or less	91
Held to Maturity, Fair Value - Due after one year through five years	89,507
Held to Maturity, Fair Value - Due after five through ten years	107,472
Held to Maturity, Fair Value - Due after ten years	3,173,842
Held to Maturity, Fair Value - Total debt securities	$ 3,370,912	$ 3,264,718