Available-For-Sale And Held-To-Maturity Securities (Contractual Maturities) (Details) - USD ($) $ in Thousands		Jun. 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]	$ 1,119
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	608,563
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	359,659
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	1,497,365
Available-for-sale Securities, debt maturities, Fair Value	[1]	2,466,706
Held-to-maturity Securities, debt maturities, after one year through five, Amortized Cost		40,112
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost		251,937
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,827,839
Held-to-maturity Securities, Amortized cost	[2]	2,119,888	$ 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]	1,081
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	1,607
Available-for-sale Securities, debt maturities, Fair Value	[1]	2,688
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]	17,362
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	57,350
Available-for-sale Securities, debt maturities, Fair Value	[1]	74,712
Corporate Fixed Income Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, debt maturities, after one year through five, Fair Value	[1]	606,956
Available-for-sale Securities, debt maturities, after five through ten years, fair value	[1]	45,137
Available-for-sale Securities, debt maturities, Fair Value	[1]	652,093
Held-to-maturity Securities, debt maturities, after one year through five, Amortized Cost		40,112
Held-to-maturity Securities, Amortized cost	[2]	40,112	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]	296,607
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	1,040,360
Available-for-sale Securities, debt maturities, Fair Value	[1]	1,336,967
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		497,242
Held-to-maturity Securities, Amortized cost	[2]	497,242	496,996
Mortgage 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		553
Availably-for-sale Securities, debt maturities, after ten years, Fair Value		399,655
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost		251,937
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,330,597
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]	553
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	394,718
Available-for-sale Securities, debt maturities, Fair Value	[1]	395,271
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost		192,386
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		1,329,824
Held-to-maturity Securities, Amortized cost	[2]	1,522,210	1,257,808
Mortgage Backed Securities [Member] | Commercial [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	2,787
Available-for-sale Securities, debt maturities, Fair Value	[1]	2,787
Held-to-maturity Securities, debt maturities, after five through ten years, Amortized Cost		59,551
Held-to-maturity Securities, Amortized cost	[2]	59,551	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]	38
Availably-for-sale Securities, debt maturities, after ten years, Fair Value	[1]	2,150
Available-for-sale Securities, debt maturities, Fair Value	[1]	2,188
Held-to-maturity Securities, debt maturities, after ten years, Amortized Cost		773
Held-to-maturity Securities, Amortized cost	[2]	$ 773	$ 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.