Accumulated Other Comprehensive Loss (Components of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (25,268)		$ (82,106)
Other comprehensive income (loss) before reclassifications	(48,859)		46,332
Amounts reclassified from accumulated other comprehensive loss	21,146	[1]	10,506	[1]
Net current period other comprehensive income (loss)	(27,713)		56,838		(15,532)
Ending balance	(52,981)		(25,268)		(82,106)
Unrealized Loss on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(4,434)	[2]	(6,292)	[2]
Other comprehensive income (loss) before reclassifications	1,770	[2]	1,858	[2]
Amounts reclassified from accumulated other comprehensive loss	0	[2]	0	[2]
Net current period other comprehensive income (loss)	1,770	[2]	1,858	[2]
Ending balance	(2,664)	[2]	(4,434)	[2]
Unrealized Gains on Investment Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(10,091)	[2]	20,517	[2]
Other comprehensive income (loss) before reclassifications	(2,683)	[2]	(30,608)	[2]
Amounts reclassified from accumulated other comprehensive loss	17,872	[1],[2]	0	[2]
Net current period other comprehensive income (loss)	15,189	[2]	(30,608)	[2]
Ending balance	5,098	[2]	(10,091)	[2]
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(10,743)	[2]	(96,331)	[2]
Other comprehensive income (loss) before reclassifications	(47,946)	[2]	75,082	[2]
Amounts reclassified from accumulated other comprehensive loss	3,274	[1],[2]	10,506	[1],[2]
Net current period other comprehensive income (loss)	(44,672)	[2]	85,588	[2]
Ending balance	$ (55,415)	[2]	$ (10,743)	[2]

[1] (Dollars in thousands) Year ended December 31, 2014Details about accumulated other comprehensive loss Amount reclassified from accumulated other comprehensive income (loss)(1) Affected line item in the statement where net income is presentedUnrealized gains and losses on available for sale securities $(29,096) Securities gains 11,224 Income taxes $(17,872) Net income Amortization of defined benefit pension items Prior service costs $(210) Employee benefitsActuarial losses (5,148) Employee benefits (5,358) Income before income taxes 2,084 Income taxes $(3,274) Net incomeTotal reclassifications for the period $(21,146) Year ended December 31, 2013Details about accumulated other comprehensive loss Amount reclassified from accumulated other comprehensive income (loss)(1) Affected line item in the statement where net income is presentedAmortization of defined benefit pension items Prior service costs $(210) Employee benefitsActuarial losses (16,985) Employee benefits (17,195) Income before income taxes 6,689 Income taxes $(10,506) Net incomeTotal reclassifications for the period $(10,506) (1) Amounts in parentheses indicate debits to profit/loss.

[2] All amounts are net of tax. Amounts in parentheses indicate debits.