Revenue Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 439,618	$ 406,814
United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	225,444	221,832
Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	97,523	83,271
Asia
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	61,373	53,924
Middle East/Africa
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	36,407	25,142
Canada/Latin America
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	18,871	22,645
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	170,658	154,785
Industrial | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	86,296	76,974
Industrial | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	35,543	33,258
Industrial | Asia
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	34,057	33,225
Industrial | Middle East/Africa
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3,665	2,332
Industrial | Canada/Latin America
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	11,097	8,996
Government and Defense
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	159,331	138,180
Government and Defense | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	95,133	91,233
Government and Defense | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	17,203	12,082
Government and Defense | Asia
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	18,351	12,021
Government and Defense | Middle East/Africa
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	27,183	18,225
Government and Defense | Canada/Latin America
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,461	4,619
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	109,629	113,849
Commercial | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	44,015	53,625
Commercial | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	44,777	37,931
Commercial | Asia
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	8,965	8,678
Commercial | Middle East/Africa
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	5,559	4,585
Commercial | Canada/Latin America
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 6,313	$ 9,030