Operating Segments and Geographic Information - Operating Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,862,716	$ 2,131,278	$ 2,165,702
Depreciation expense	42,500	40,400	38,300
Amortization of intangibles	64,395	74,609	75,140
Severance, restructuring, and acquisition integration costs	12,258	26,544	22,625
Acquisition of property, plant and equipment	90,215	110,002	97,847
Segment assets	3,139,734	3,406,759	3,779,321
Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	872,417	946,041	957,501
Severance, restructuring, and acquisition integration costs	7,719	10,808	14,863
Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	990,299	1,185,237	1,208,201
Severance, restructuring, and acquisition integration costs	4,539	15,736	7,762
Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,862,716	2,131,278	2,165,702
Segment EBITDA	246,959	353,035	394,660
Depreciation expense	42,470	40,409	38,309
Amortization of intangibles	64,395	74,609	75,140
Amortization of software development intangible assets	1,821	525	79
Severance, restructuring, and acquisition integration costs	12,258	26,544	22,625
Purchase accounting effects of acquisitions	125	592	1,690
Acquisition of property, plant and equipment	69,898	77,478	72,153
Segment assets	985,252	991,607	938,971
Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Segment EBITDA	99,333	126,925	156,790
Depreciation expense	20,655	19,771	18,490
Amortization of intangibles	21,662	22,324	21,076
Severance, restructuring, and acquisition integration costs	7,720	10,808	14,863
Purchase accounting effects of acquisitions	125	592	1,690
Acquisition of property, plant and equipment	25,223	42,289	42,624
Segment assets	462,615	487,125	430,128
Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Segment EBITDA	147,626	226,110	237,870
Depreciation expense	21,815	20,638	19,819
Amortization of intangibles	42,733	52,285	54,064
Severance, restructuring, and acquisition integration costs	4,538	15,736	7,762
Acquisition of property, plant and equipment	44,675	35,189	29,529
Segment assets	522,637	504,482	508,843
Software Development | Reportable Segment
Segment Reporting Information [Line Items]
Amortization of intangibles	1,821	525	79
Software Development | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Amortization of software development intangible assets	245	175	71
Software Development | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Amortization of software development intangible assets	1,576	350	8
Segment revenues | Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,862,716	2,131,278	2,165,702
Segment revenues | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	872,415	946,041	957,501
Segment revenues | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	990,301	1,185,237	1,208,201
Affiliate revenues | Reportable Segment
Segment Reporting Information [Line Items]
Revenues	1,349	4,173	6,185
Affiliate revenues | Reportable Segment | Enterprise Solutions
Segment Reporting Information [Line Items]
Revenues	1,289	4,162	6,105
Affiliate revenues | Reportable Segment | Industrial Solutions
Segment Reporting Information [Line Items]
Revenues	$ 60	$ 11	$ 80