Operations and Summary of Significant Accounting Policies - Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in gross carrying amount of finite-lived intangible assets
Gross carrying amount, balance at the beginning of the year	$ 58,874
Accumulated amortization, balance at the beginning of the year	(26,287)
Intangible assets, net carrying amount, beginning of period	32,587
Amortization	(6,100)	$ (7,200)	$ (7,100)
Foreign exchange		(1,479)
Acquisition	1,062
Gross carrying amount, balance at the end of the year	57,065	58,874
Accumulated amortization, balance at the end of the year	(29,390)	(26,287)
Intangible assets, net carrying amount, end of period	27,675	32,587
Estimated future amortization of intangible assets
2016	6,054
2017	4,166
2018	3,130
2019	3,101
2020	3,072
Thereafter	6,024
Total	25,547
Noncompete Agreements Trademarks and Other
Changes in gross carrying amount of finite-lived intangible assets
Gross carrying amount, balance at the beginning of the year	10,839	13,555
Accumulated amortization, balance at the beginning of the year	(5,374)	(3,554)
Intangible assets, net carrying amount, beginning of period	5,465	10,001
Amortization	(2,039)	(2,020)
Reclassifications		(2,554)
Foreign exchange	(76)	(62)
Acquisition	25	100
Removal of fully amortized asset, gross	(210)	(200)
Accumulated amortization of removal of fully amortized asset	210	200
Finite Lived Intangible Assets Removal of Fully Amortized Assets, Net	0	0
Gross carrying amount, balance at the end of the year	10,578	10,839	13,555
Accumulated amortization, balance at the end of the year	(7,203)	(5,374)	(3,554)
Intangible assets, net carrying amount, end of period	3,375	5,465	10,001
Patents
Changes in gross carrying amount of finite-lived intangible assets
Gross carrying amount, balance at the beginning of the year	1,758	6,689
Accumulated amortization, balance at the beginning of the year	(1,577)	(5,988)
Intangible assets, net carrying amount, beginning of period	181	701
Amortization	(102)	(506)
Foreign exchange	(7)	(14)
Removal of fully amortized asset, gross	(1,300)	(4,917)
Accumulated amortization of removal of fully amortized asset	1,300	4,917
Finite Lived Intangible Assets Removal of Fully Amortized Assets, Net	0	0
Gross carrying amount, balance at the end of the year	1,513	1,758	6,689
Accumulated amortization, balance at the end of the year	(379)	(1,577)	(5,988)
Intangible assets, net carrying amount, end of period	1,134	181	701
Unpatented Technology
Changes in gross carrying amount of finite-lived intangible assets
Gross carrying amount, balance at the beginning of the year	22,797	18,977
Accumulated amortization, balance at the beginning of the year	(7,665)	(5,257)
Intangible assets, net carrying amount, beginning of period	15,132	13,720
Amortization	(2,061)	(2,408)
Reclassifications		(5,299)
Foreign exchange	(123)	(1,479)
Removal of fully amortized asset, gross	(1,070)
Accumulated amortization of removal of fully amortized asset	1,070
Finite Lived Intangible Assets Removal of Fully Amortized Assets, Net	0
Gross carrying amount, balance at the end of the year	21,604	22,797	18,977
Accumulated amortization, balance at the end of the year	(8,656)	(7,665)	(5,257)
Intangible assets, net carrying amount, end of period	12,948	15,132	13,720
Customer Relationships
Changes in gross carrying amount of finite-lived intangible assets
Gross carrying amount, balance at the beginning of the year	21,346	22,849
Accumulated amortization, balance at the beginning of the year	(11,671)	(11,164)
Intangible assets, net carrying amount, beginning of period	9,675	11,685
Amortization	(1,881)	(2,225)
Reclassifications		(658)
Foreign exchange	(178)	(443)
Acquisition	474
Removal of fully amortized asset, gross	(400)	(1,718)
Accumulated amortization of removal of fully amortized asset	400	1,718
Finite Lived Intangible Assets Removal of Fully Amortized Assets, Net	0	0
Gross carrying amount, balance at the end of the year	21,242	21,346	22,849
Accumulated amortization, balance at the end of the year	(13,152)	(11,671)	(11,164)
Intangible assets, net carrying amount, end of period	$ 8,090	$ 9,675	$ 11,685