Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019		Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances	$ 647,360	$ 640,510	$ 620,450	$ 585,690	$ 565,780	$ 544,020	$ 620,450		$ 544,020
Total other comprehensive income (loss)	180	(1,530)	3,020	(1,980)	1,910	(1,480)	1,670		(1,550)
Balances	662,060	647,360	640,510	607,490	585,690	565,780	662,060		607,490
Other Comprehensive Income (Loss), Tax [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax							(1,800)		500
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax							100		900
Defined Benefit Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances			(7,200)			(10,450)	(7,200)		(10,450)
Net unrealized gains (losses) arising during the period							0		0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							(300)	[1]	(3,030)	[2]
Total other comprehensive income (loss)							300		3,030
Reclassification of stranded tax effects							(1,260)
Balances	(8,160)			(7,420)			(8,160)		(7,420)
Accumulated Net Gain (Loss) from Hedges Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances			940			(3,170)	940		(3,170)
Net unrealized gains (losses) arising during the period							5,750	[3]	1,720	[4]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							0		0
Total other comprehensive income (loss)							5,750		1,720
Reclassification of stranded tax effects							(10)
Balances	6,680			(1,450)			6,680		(1,450)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances			(10,590)			(3,710)	(10,590)		(3,710)
Net unrealized gains (losses) arising during the period							(4,380)		(6,300)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							0		0
Total other comprehensive income (loss)							(4,380)		(6,300)
Reclassification of stranded tax effects							0
Balances	(14,970)			(10,010)			(14,970)		(10,010)
Accumulated Other Comprehensive Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balances	(16,630)	(15,100)	(16,850)	(16,900)	(18,810)	(17,330)	(16,850)		(17,330)
Net unrealized gains (losses) arising during the period							1,370		(4,580)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							(300)		(3,030)
Total other comprehensive income (loss)	180	(1,530)	3,020	(1,980)	1,910	(1,480)	1,670		(1,550)
Reclassification of stranded tax effects							(1,270)
Balances	$ (16,450)	$ (16,630)	$ (15,100)	$ (18,880)	$ (16,900)	$ (18,810)	$ (16,450)		$ (18,880)

[1] Defined benefit plans, net of income tax of approximately $0.1 million. See Note 16, "Defined Benefit Plans," for further details.

[2] Defined benefit plans, net of income tax of approximately $0.9 million. See Note 16, "Defined Benefit Plans," for further details.

[3] Derivative instruments, net of income tax of approximately $1.8 million. See Note 10, "Derivative Instruments," for further details.

[4] Derivative instruments, net of income tax of approximately $0.5 million. See Note 10, "Derivative Instruments," for further details.