Investment Securities (Schedule Of Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Available-for-sale securities, three months or less, amortized cost	$ 4,655
Available-for-sale securities, over three months through twelve months, amortized cost	101,270
Available-for-sale securities, after one year through five years, amortized cost	1,607,293
Available-for-sale securities, after five years through ten years, amortized cost	531,111
Available-for-sale securities, after ten years, amortized cost	198,801
Available-for-sale securities, amortized cost	2,445,089
Available-for-sale securities, three months or less, fair value	4,665
Available-for-sale securities, over three months through twelve months, fair value	102,536
Available-for-sale securities, after one year through five years, fair value	1,630,492
Available-for-sale securities, after five years through ten years, fair value	540,023
Available-for-sale securities, after ten years, fair value	202,313
Available-for-sale securities, fair value	2,482,072
Held-to-maturity securities, three months or less, amortized cost	0
Held-to-maturity securities, over three months through twelve months, amortized cost	4
Held-to-maturity securities, after one year through five years, amortized cost	188
Held-to-maturity securities, after five years through ten years, amortized cost	367
Held-to-maturity securities, after ten years, amortized cost	3,823
Investment securities held to maturity	4,382	$ 4,609
Held-to-maturity securities, three months or less, fair value	0
Held-to-maturity securities, over three months through twelve months, fair value	4
Held-to-maturity securities, after one year through five years, fair value	496
Held-to-maturity securities, after five years through ten years, fair value	857
Held-to-maturity securities, after ten years, fair value	3,893
Held-to-maturity securities, fair value	5,250	$ 5,590
Other Investment Securities
Investment Holdings [Line Items]
Available-for-sale securities, amortized cost	1,959
Available-for-sale securities, fair value	2,043
Investment securities held to maturity	0
Held-to-maturity securities, fair value	$ 0