Accumulated Other Comrehensive Loss (Components of AOCI) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		$ (64,440)	$ (52,981)
Other comprehensive (loss) income before reclassifications		(58,401)	(11,378)
Amounts reclassified from accumulated other comprehensive (loss) income	[1]	(12,351)	(81)
Net current period other comprehensive (loss) income		(70,752)	(11,459)	$ (27,713)
Ending balance		(135,192)	(64,440)	(52,981)
Unrealized Loss on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]	(892)	(2,664)
Other comprehensive (loss) income before reclassifications	[2]	892	1,772
Amounts reclassified from accumulated other comprehensive (loss) income	[2]	0	0
Net current period other comprehensive (loss) income	[2]	892	1,772
Ending balance	[2]	0	(892)	(2,664)
Unrealized Gains on Investment Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]	(15,125)	5,098
Other comprehensive (loss) income before reclassifications	[2]	(13,946)	(13,544)
Amounts reclassified from accumulated other comprehensive (loss) income	[1],[2]	(16,804)	(6,679)
Net current period other comprehensive (loss) income	[2]	(30,750)	(20,223)
Ending balance	[2]	(45,875)	(15,125)	5,098
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	[2]	(48,423)	(55,415)
Other comprehensive (loss) income before reclassifications	[2]	(45,347)	394
Amounts reclassified from accumulated other comprehensive (loss) income	[1],[2]	4,453	6,598
Net current period other comprehensive (loss) income	[2]	(40,894)	6,992
Ending balance	[2]	$ (89,317)	$ (48,423)	$ (55,415)

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

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