Available-For-Sale And Held-To-Maturity Securities (Contractual Maturities) (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, within one year, Fair Value	[1]	$ 23,597
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	681,220
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	679,317
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	1,761,133
Available-for-sale Securities, debt maturities, Fair Value	[1]	3,145,267
Held-to-maturity Securities, debt maturities, after one year through five, Amortized Cost		99,661
Held-to-maturity Securities, debt maturities, after five year through ten, Amortized Cost		181,413
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,960,129
Held-to-maturity Securities, Amortized cost	[2]	2,241,203	$ 1,855,399
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, within one year, Fair Value	[1]	1,428
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	3,018
Available-for-sale Securities, debt maturities, Fair Value	[1]	4,446
State And Municipal Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	17,337
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	56,523
Available-for-sale Securities, debt maturities, Fair Value	[1]	73,860
Corporate Fixed Income Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, within one year, Fair Value	[1]	22,146
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	678,202
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	128,422
Available-for-sale Securities, debt maturities, Fair Value	[1]	828,770
Held-to-maturity Securities, debt maturities, after one year through five, Amortized Cost		40,095
Held-to-maturity Securities, Amortized cost	[2]	40,095	40,145
Asset-Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	474,884
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	1,318,309
Available-for-sale Securities, debt maturities, Fair Value	[1]	1,793,193
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		497,362
Held-to-maturity Securities, Amortized cost	[2]	497,362	496,996
Mortgage Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, within one year, Fair Value		23
Available-for-sale Securities, debt maturities, after five through ten years, fair value		58,674
Availably-for-sale Securities, debt maturities, after ten years, Fair Value		386,301
Held-to-maturity Securities, debt maturities, after five year through ten, Amortized Cost		181,413
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,462,768
Mortgage Backed Securities [Member] | Agency [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	517
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	365,119
Available-for-sale Securities, debt maturities, Fair Value	[1]	365,636
Held-to-maturity Securities, debt maturities, after five year through ten, Amortized Cost		181,413
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,462,066
Held-to-maturity Securities, Amortized cost	[2]	1,643,479	1,257,808
Mortgage Backed Securities [Member] | Commercial [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	58,157
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	19,114
Available-for-sale Securities, debt maturities, Fair Value	[1]	77,271
Held-to-maturity Securities, debt maturities, after one year through five, Amortized Cost		59,566
Held-to-maturity Securities, Amortized cost	[2]	59,566	59,521
Mortgage Backed Securities [Member] | Non-Agency [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, within one year, Fair Value	[1]	23
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	2,068
Available-for-sale Securities, debt maturities, Fair Value	[1]	2,091
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		701
Held-to-maturity Securities, Amortized cost	[2]	$ 701	$ 929

[1] Due to the immaterial amount of income recognized on tax-exempt securities, yields were not calculated on a tax-equivalent basis.

[2] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.