CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net actuarial gain (loss), tax expense (benefit)	$ (1,011)	$ 822	$ (2,010)	$ (2,637)
Pension settlement expense, tax	366	313	1,417	882
Amortization of unrecognized net periodic benefit costs, tax	331	496	1,084	1,410
Change in unrealized income (loss) on interest rate swap, tax expense (benefit)	16	168	156	(278)
Change in foreign currency translation, tax expense (benefit)	$ 190	$ (127)	$ 132	$ 158