Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016		Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period				$ 635,786
Other comprehensive income (loss) before reclassifications (4)				16,295	[1]	$ 5,197
Actuarial net gain (loss) incurred in the fiscal year	[1]			334
Amounts reclassified from accumulated other comprehensive (income) loss				143	[1]	82	[2]
Other comprehensive income (loss)		$ 12,717	$ (5,688)	16,772		5,279
Balance, End of Period		718,255		718,255
AOCI, Pension and other postretirement benefit plans, tax		8,961	9,840	8,961		9,840		$ 9,160	$ 9,879
AOCI, Cumulative changes in net gain (loss) from cash flow hedges, tax		187	0	187		0		$ 0	$ 5
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period				(46,446)		(41,365)
Other comprehensive income (loss) before reclassifications (4)				16,730	[1]	5,197
Actuarial net gain (loss) incurred in the fiscal year	[1]			0
Amounts reclassified from accumulated other comprehensive (income) loss				0	[1]	0	[2]
Other comprehensive income (loss)				16,730		5,197
Balance, End of Period		(29,716)	(36,168)	(29,716)		(36,168)
Funded status of pension plans and other postretirement benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	[3]			(45,816)		(47,082)
Other comprehensive income (loss) before reclassifications (4)	[3]			0	[1]	0
Actuarial net gain (loss) incurred in the fiscal year	[1],[3]			334
Amounts reclassified from accumulated other comprehensive (income) loss	[3]			36	[1]	71	[2]
Other comprehensive income (loss)	[3]			370		71
Balance, End of Period	[3]	(45,446)	(47,011)	(45,446)		(47,011)
Reclassification from AOCI, Current Period, Tax				39		199
Unrealized gain (loss) on derivative instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period	[4]			0		(11)
Other comprehensive income (loss) before reclassifications (4)	[1],[4]			(435)
Actuarial net gain (loss) incurred in the fiscal year	[1],[4]			0
Amounts reclassified from accumulated other comprehensive (income) loss	[4]			107	[1]	11	[2]
Other comprehensive income (loss)	[4]			(328)		11
Balance, End of Period	[4]	(328)	0	(328)		0
Reclassification from AOCI, Current Period, Tax				5		(187)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, Beginning of Period				(92,262)		(88,458)
Other comprehensive income (loss)				16,772
Balance, End of Period		$ (75,490)	$ (83,179)	$ (75,490)		$ (83,179)

[1] (4) Net of taxes of $199 and $(187) for the pension plans and postretirement benefits and unrealized gain (loss) on derivatives, respectively.

[2] (3) Net of taxes of $39 and $5 for the pension plans and postretirement benefits and unrealized gain (loss) on derivatives, respectively.

[3] (1) Net of taxes of $8,961 and $9,160 as of June 30, 2017 and December 31, 2016, respectively. Net of taxes of $9,840 and $9,879 as of June 30, 2016 and December 31, 2015, respectively.

[4] (2) Net of taxes of $187 and $0 as of June 30, 2017 and December 31, 2016, respectively. Net of taxes of $0 and $5 as of June 30, 2016 and December 31, 2015, respectively.