Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances		$ 544,020
Total other comprehensive income (loss)		(1,480)		$ 2,350
Balances		565,780
Other Comprehensive Income (Loss), Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax		(1,200)		100
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax		100		100
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax				(100)
Defined Benefit Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances		(10,450)		(12,120)
Net unrealized gains (losses) arising during the period		0		0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(200)	[1]	(170)	[2]
Total other comprehensive income (loss)		200		170
Balances		(10,250)		(11,950)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances				(2,520)
Net unrealized gains (losses) arising during the period	[3]			240
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			(140)
Total other comprehensive income (loss)				380
Balances				(2,140)
Accumulated Net Gain (Loss) from Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances		(3,170)
Net unrealized gains (losses) arising during the period	[4]	(4,040)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Total other comprehensive income (loss)		(4,040)
Balances		(7,210)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances		(3,710)		(9,760)
Net unrealized gains (losses) arising during the period		2,360		1,800
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0		0
Total other comprehensive income (loss)		2,360		1,800
Balances		(1,350)		(7,960)
Accumulated Other Comprehensive Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances		(17,330)		(24,400)
Net unrealized gains (losses) arising during the period		(1,680)		2,040
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(200)		(310)
Total other comprehensive income (loss)		(1,480)		2,350
Balances		$ (18,810)		$ (22,050)

[1] Defined benefit plans, net of income tax of approximately $0.1 million. See Note 14, "Defined Benefit Plans," for further details.

[2] Defined benefit plans, net of income tax of approximately $0.1 million. See Note 14, "Defined Benefit Plans," for further details. Derivative instruments, net of income tax of approximately $0.1 million. See Note 9, "Derivative Instruments," for further details.

[3] Derivative instruments, net of income tax of approximately $0.1 million. See Note 9, "Derivative Instruments," for further details.

[4] Derivative instruments, net of income tax of approximately $1.2 million. See Note 9, "Derivative Instruments," for further details.