Accumulated Other Comprehensive Loss (Reclassifications out of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Long-term obligations	$ 740,186		$ 914,688		$ 870,967
Securities gains (losses)	0		2,277		(288)
Income taxes	(96,965)		(59,822)		(115,103)
Amounts reclassified from accumulated other comprehensive income, net of tax	12,424	[1]	7,304	[1]
Unrealized Loss on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Long-term obligations	(3,281)	[1]	(3,095)	[1]
Income taxes	1,363	[1]	1,222	[1]
Amounts reclassified from accumulated other comprehensive income, net of tax	1,918	[1],[2]	1,873	[1],[2]
Unrealized Gains on Investment Securities Available for Sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)	0	[1]	2,322	[1]
Income taxes	0	[1]	(917)	[1]
Amounts reclassified from accumulated other comprehensive income, net of tax	0	[1],[2]	(1,405)	[1],[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	(16,985)	[1]	(11,026)	[1]
Total before taxes	(17,195)		(11,236)	[1]
Income taxes	6,689	[1]	4,400	[1]
Amounts reclassified from accumulated other comprehensive income, net of tax	$ 10,506	[1],[2]	$ 6,836	[1],[2]

[1] 1 Amounts in parentheses indicate debits to profit/loss.

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