Accumulated Other Comprehensive Loss (Components of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (16,594)		$ (79,905)		$ (25,268)		$ (82,106)
Other comprehensive income before reclassifications	19,675		(22,883)		27,372		(23,301)
Amounts reclassified from accumulated other comprehensive loss	976		2,612		1,953		5,231
Net current period other comprehensive income	20,651		(20,271)		29,325		(18,070)
Ending balance	4,057		(100,176)		4,057		(100,176)
Unrealized Loss on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,993)	[1]	(5,799)	[1]	(4,434)	[1]	(6,292)	[1]
Other comprehensive income before reclassifications	350	[1]	840	[1]	791	[1]	1,333	[1]
Amounts reclassified from accumulated other comprehensive loss	0	[1]	0	[1]	0	[1]	0	[1]
Net current period other comprehensive income	350	[1]	840	[1]	791	[1]	1,333	[1]
Ending balance	(3,643)	[1]	(4,959)	[1]	(3,643)	[1]	(4,959)	[1]
Unrealized Gains on Investment Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,835)	[1]	19,606	[1]	(10,091)	[1]	20,517	[1]
Other comprehensive income before reclassifications	19,325	[1]	(23,723)	[1]	26,581	[1]	(24,634)	[1]
Amounts reclassified from accumulated other comprehensive loss	0	[1]	0	[1]	0	[1]	0	[1]
Net current period other comprehensive income	19,325	[1]	(23,723)	[1]	26,581	[1]	(24,634)	[1]
Ending balance	16,490	[1]	(4,117)	[1]	16,490	[1]	(4,117)	[1]
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(9,766)	[1]	(93,712)	[1]	(10,743)	[1]	(96,331)	[1]
Other comprehensive income before reclassifications	0	[1]	0	[1]	0	[1]	0	[1]
Amounts reclassified from accumulated other comprehensive loss	976	[1]	2,612	[1]	1,953	[1]	5,231	[1]
Net current period other comprehensive income	976	[1]	2,612	[1]	1,953	[1]	5,231	[1]
Ending balance	$ (8,790)	[1]	$ (91,100)	[1]	$ (8,790)	[1]	$ (91,100)	[1]

[1] All amounts are net of tax.