Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Services	$ 327,742	$ 328,791
United States
Disaggregation of Revenue [Line Items]
Services	264,561	263,017
Canada
Disaggregation of Revenue [Line Items]
Services	18,256	22,378
Other
Disaggregation of Revenue [Line Items]
Services	44,925	43,396
Food & Beverage
Disaggregation of Revenue [Line Items]
Services	58,091	66,663
Retail
Disaggregation of Revenue [Line Items]
Services	36,303	32,580
Consumer Products
Disaggregation of Revenue [Line Items]
Services	39,769	35,001
Communications
Disaggregation of Revenue [Line Items]
Services	41,045	39,798
Automotive
Disaggregation of Revenue [Line Items]
Services	25,192	18,191
Technology
Disaggregation of Revenue [Line Items]
Services	25,535	26,616
Healthcare
Disaggregation of Revenue [Line Items]
Services	24,066	23,297
Financials
Disaggregation of Revenue [Line Items]
Services	24,005	25,126
Transportation and Travel/Lodging
Disaggregation of Revenue [Line Items]
Services	20,486	17,441
Other
Disaggregation of Revenue [Line Items]
Services	$ 33,250	$ 44,078