Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net unrealized gain (loss) on cash flow hedges, tax	$ 79	$ 420	$ 219	$ 925
Net unrealized loss on investment securities, tax	721	(546)	(142)	1,908
Amortization of pension and postretirement costs, tax	$ 4,219	$ 3,355	$ 12,001	$ 10,609