Accumulated Other Comprehensive Loss (Reclassifications out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Long-term obligations	$ 710,097		$ 740,186		$ 914,688
Securities gains (losses)	29,096		0		2,277
Income taxes	(65,032)		(101,574)		(64,729)
Amounts reclassified from accumulated other comprehensive income, net of tax	21,146	[1]	10,506	[1]
Unrealized Loss on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax	0	[2]	0	[2]
Unrealized Gains on Investment Securities Available for Sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)	(29,096)	[1]
Income taxes	11,224	[1]
Amounts reclassified from accumulated other comprehensive income, net of tax	17,872	[1],[2]	0	[2]
Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Employee Benefits, prior service costs	(210)	[1]	(210)	[1]
Reclassification adjustment for losses included in income before income taxes	(5,148)	[1]	(16,985)	[1]
Total before taxes	(5,358)		(17,195)	[1]
Income taxes	2,084	[1]	6,689	[1]
Amounts reclassified from accumulated other comprehensive income, net of tax	$ 3,274	[1],[2]	$ 10,506	[1],[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.