Acquisitions (Details) - USD ($) $ in Thousands				1 Months Ended	12 Months Ended
	Nov. 23, 2016	Dec. 21, 2015	Jan. 22, 2015	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life					6 years 7 months 6 days
Amortization expense					$ 11,200	$ 10,900	$ 6,100
Estimated future amortization expense for 2017				$ 15,300	15,300
Estimated future amortization expense for 2018				14,700	14,700
Estimated future amortization expense for 2019				14,300	14,300
Estimated future amortization expense for 2020				10,800	10,800
Estimated future amortization expense for 2021				9,900	9,900
Proceeds from the sale of a business		$ 1,265			0	1,265	0
Loss on disposition of a business		$ 4,800			$ 0	4,819	$ 0
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life					7 years 8 months 12 days
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life					5 years
Covenant-not-to-compete
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life					2 years 6 months
DeWAL
Finite-Lived Intangible Assets [Line Items]
Purchase price	$ 136,000
Cash from credit facility used to fund acquisition	136,000
Estimated future amortization expense for 2017				5,300	$ 5,300
Estimated future amortization expense for 2018				5,300	5,300
Estimated future amortization expense for 2019				5,300	5,300
Estimated future amortization expense for 2020				5,300	5,300
Estimated future amortization expense for 2021				5,200	5,200
Transaction costs					$ 2,100
Business acquisition, acquiree revenue				5,400
Business acquisition, acquiree net income				2,000
DeWAL | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	46,700
Weighted average useful life					9 years 7 months 6 days
DeWAL | Developed technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	22,000
Weighted average useful life					6 years 3 months 18 days
DeWAL | Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life					3 years 4 months 24 days
DeWAL | Covenant-not-to-compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 500
Weighted average useful life					2 years 6 months
Arlon
Finite-Lived Intangible Assets [Line Items]
Purchase price			$ 157,000
Cash from credit facility used to fund acquisition			125,000
Estimated future amortization expense for 2017				5,800	$ 5,800
Estimated future amortization expense for 2018				5,800	5,800
Estimated future amortization expense for 2019				$ 5,800	$ 5,800
Transaction costs						1,500
Business acquisition, acquiree revenue						100,000
Business acquisition, acquiree net income						$ 25,100
Arlon | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			32,700
Weighted average useful life					6 years
Arlon | Developed technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			15,800
Weighted average useful life					5 years 8 months 12 days
Arlon | Trademarks
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 1,600
Weighted average useful life					3 years 2 months 12 days
Minimum | DeWAL
Finite-Lived Intangible Assets [Line Items]
Amortization expense					$ 4,300
Minimum | Arlon
Finite-Lived Intangible Assets [Line Items]
Amortization expense					1,800
Maximum | DeWAL
Finite-Lived Intangible Assets [Line Items]
Amortization expense					5,300
Maximum | Arlon
Finite-Lived Intangible Assets [Line Items]
Amortization expense					$ 5,800