Other Comprehensive Income/Loss (Components of Accumulated Other Comprehensive Loss, Net of Related Tax Effects) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Comprehensive Income
Balance at the beginning of the period	$ (65,807)	$ (30,201)	$ (65,951)	$ (38,250)
Other comprehensive income, net of tax	3,374	(333)	3,518	7,716
Balance at the end of the period	(62,433)	(30,534)	(62,433)	(30,534)
Net unrealized (loss) gain on securities available-for-sale
Other Comprehensive Income
Balance at the beginning of the period	3,888	3,326	4,686	(4,366)
Other comprehensive income, net of tax	2,903	(511)	2,105	7,181
Balance at the end of the period	6,791	2,815	6,791	2,815
Net actuarial loss on pension plans and other postretirement benefits
Other Comprehensive Income
Balance at the beginning of the period	(66,590)	(30,304)	(67,476)	(30,600)
Other comprehensive income, net of tax	442	147	1,328	443
Balance at the end of the period	(66,148)	(30,157)	(66,148)	(30,157)
Prior service cost on pension plans and other postretirement benefits
Other Comprehensive Income
Balance at the beginning of the period	(3,105)	(3,223)	(3,161)	(3,284)
Other comprehensive income, net of tax	29	31	85	92
Balance at the end of the period	$ (3,076)	$ (3,192)	$ (3,076)	$ (3,192)