Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)		$ 4,628	$ 5,126
Amortization of actuarial losses and prior service cost		1,652	2,886
Amounts reclassified from accumulated other comprehensive income, net of tax		(1,838)	(1,386)
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	[1]	0	0
Unrealized Gains on Investment Securities Available for Sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)		4,628	5,126
Income taxes		(1,770)	(1,977)
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	(2,858)	(3,149)
Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Employee Benefits, prior service costs		(52)	(53)
Amortization of actuarial losses and prior service cost		(1,600)	(2,833)
Total before taxes		(1,652)	(2,886)
Income taxes		632	1,123
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	$ 1,020	$ 1,763

[1] All amounts are net of tax.