Accumulated Other Comprehensive Income (Loss) (Reclassifications out of AOCI) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale securities reclassified from AOCI before tax		$ 352	$ 5,564	$ 17,509	$ 10,837
Securities gains (losses)		352	5,564	17,509	10,837
Amortization of actuarial losses and prior service cost		(1,714)	(2,863)	(5,144)	(8,531)
Total before taxes		(1,768)	(2,916)	(5,302)	(8,689)
Amounts reclassified from accumulated other comprehensive income, net of tax		965	(1,632)	(7,617)	(1,327)
Unrealized gains and losses on available for sale securities reclassified from AOCI tax		(191)	(2,094)	(6,583)	(4,145)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		161	3,470	10,926	6,692
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax		(54)	(53)	(158)	(158)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax		642	1,078	1,993	3,324
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax		(1,126)	(1,838)	(3,309)	(5,365)
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	0	0
Unrealized Gains on Investment Securities Available for Sale
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	(161)	(3,470)	(10,926)	(6,692)
Defined Benefit Pension Items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax	[1]	$ 1,126	$ 1,838	$ 3,309	$ 5,365

[1] All amounts are net of tax.