Other Comprehensive Income (Loss) (Changes in Accumulated Other Comprehensive Income (Loss) by Component (Net of Income Taxes)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	$ (29,819)	$ (12,605)
Other comprehensive income (loss) before reclassifications	29,010	9,355
Amounts reclassified from accumulated other comprehensive income (loss)	69	(401)
Net current period other comprehensive income (loss)	29,079	8,954
Ending balance	(740)	(3,651)
Net Unrealized Gains (Losses) on Cash Flow Hedges [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	(12,504)	(12,824)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	168	69
Net current period other comprehensive income (loss)	168	69
Ending balance	(12,336)	(12,755)
Net Unrealized Gains (Losses) on Investment Securities Available for Sale [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	(18,222)	(713)
Other comprehensive income (loss) before reclassifications	29,010	9,355
Amounts reclassified from accumulated other comprehensive income (loss)	(41)	(444)
Net current period other comprehensive income (loss)	28,969	8,911
Ending balance	10,747	8,198
Post-Retirement Unfunded Health Benefit [Member]
Changes in Accumulated Other Comprehensive Income (Loss) by Component [Roll Forward]
Beginning balance	907	932
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	(58)	(26)
Net current period other comprehensive income (loss)	(58)	(26)
Ending balance	$ 849	$ 906