Investment Securities Available for Sale (Amortized Cost And Estimated Fair Value By Contractual Maturity Of Investment Securities Available For Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	$ 10,208
Amortized Cost, 1 to 5 Years	302,918
Amortized Cost, 5 to 10 Years	1,467,259
Amortized Cost, More Than 10 years	1,147,597
Amortized Cost, Amortized Cost, No Stated Maturity	3,648
Total Amortized Cost	2,931,630
Fair Value, Within One year	10,407
Fair Value, 1 to 5 Years	307,640
Fair Value, 5 to 10 Years	1,480,754
Fair Value, More Than 10 years	1,178,571
Fair Value, No Stated Maturity	3,740
Total Fair Value	2,981,112
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	356
Amortized Cost, 1 to 5 Years	0
Amortized Cost, 5 to 10 Years	0
Amortized Cost, More Than 10 years	0
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	356
Fair Value, Within One year	356
Fair Value, 1 to 5 Years	0
Fair Value, 5 to 10 Years	0
Fair Value, More Than 10 years	0
Fair Value, No Stated Maturity	0
Total Fair Value	356
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	0
Amortized Cost, 1 to 5 Years	1,265
Amortized Cost, 5 to 10 Years	32,498
Amortized Cost, More Than 10 years	2,028
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	35,791
Fair Value, Within One year	0
Fair Value, 1 to 5 Years	1,433
Fair Value, 5 to 10 Years	34,185
Fair Value, More Than 10 years	2,428
Fair Value, No Stated Maturity	0
Total Fair Value	38,046
Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	4,499
Amortized Cost, 1 to 5 Years	285,024
Amortized Cost, 5 to 10 Years	0
Amortized Cost, More Than 10 years	0
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	289,523
Fair Value, Within One year	4,582
Fair Value, 1 to 5 Years	288,728
Fair Value, 5 to 10 Years	0
Fair Value, More Than 10 years	0
Fair Value, No Stated Maturity	0
Total Fair Value	293,310
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	3
Amortized Cost, 1 to 5 Years	271
Amortized Cost, 5 to 10 Years	1
Amortized Cost, More Than 10 years	238,106
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	238,381
Fair Value, Within One year	3
Fair Value, 1 to 5 Years	286
Fair Value, 5 to 10 Years	1
Fair Value, More Than 10 years	245,303
Fair Value, No Stated Maturity	0
Total Fair Value	245,593
Mortgage-Backed Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	2,077
Amortized Cost, 1 to 5 Years	9,922
Amortized Cost, 5 to 10 Years	1,432,263
Amortized Cost, More Than 10 years	387,814
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	1,832,076
Fair Value, Within One year	2,158
Fair Value, 1 to 5 Years	10,532
Fair Value, 5 to 10 Years	1,443,976
Fair Value, More Than 10 years	410,827
Fair Value, No Stated Maturity	0
Total Fair Value	1,867,493
Collateralized Mortgage-Backed Securities Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	0
Amortized Cost, 1 to 5 Years	0
Amortized Cost, 5 to 10 Years	532
Amortized Cost, More Than 10 years	513,105
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	513,637
Fair Value, Within One year	0
Fair Value, 1 to 5 Years	0
Fair Value, 5 to 10 Years	541
Fair Value, More Than 10 years	513,948
Fair Value, No Stated Maturity	0
Total Fair Value	514,489
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	3,273
Amortized Cost, 1 to 5 Years	6,436
Amortized Cost, 5 to 10 Years	1,965
Amortized Cost, More Than 10 years	3,544
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	15,218
Fair Value, Within One year	3,308
Fair Value, 1 to 5 Years	6,661
Fair Value, 5 to 10 Years	2,051
Fair Value, More Than 10 years	3,778
Fair Value, No Stated Maturity	0
Total Fair Value	15,798
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	0
Amortized Cost, 1 to 5 Years	0
Amortized Cost, 5 to 10 Years	0
Amortized Cost, More Than 10 years	0
Amortized Cost, Amortized Cost, No Stated Maturity	3,648
Total Amortized Cost	3,648
Fair Value, Within One year	0
Fair Value, 1 to 5 Years	0
Fair Value, 5 to 10 Years	0
Fair Value, More Than 10 years	0
Fair Value, No Stated Maturity	3,740
Total Fair Value	3,740
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Within One year	0
Amortized Cost, 1 to 5 Years	0
Amortized Cost, 5 to 10 Years	0
Amortized Cost, More Than 10 years	3,000
Amortized Cost, Amortized Cost, No Stated Maturity	0
Total Amortized Cost	3,000
Fair Value, Within One year	0
Fair Value, 1 to 5 Years	0
Fair Value, 5 to 10 Years	0
Fair Value, More Than 10 years	2,287
Fair Value, No Stated Maturity	0
Total Fair Value	$ 2,287