Goodwill and Intangible Assets - Estimated Useful Lives (Details)	6 Months Ended
	Jun. 30, 2019
Customer relationships | Minimum
Intangible Assets [Abstract]
Estimated useful lives (in years)	5 years
Customer relationships | Maximum
Intangible Assets [Abstract]
Estimated useful lives (in years)	10 years
Non-compete agreements | Minimum
Intangible Assets [Abstract]
Estimated useful lives (in years)	3 years
Non-compete agreements | Maximum
Intangible Assets [Abstract]
Estimated useful lives (in years)	5 years
Customer backlog | Minimum
Intangible Assets [Abstract]
Estimated useful lives (in years)	9 months
Customer backlog | Maximum
Intangible Assets [Abstract]
Estimated useful lives (in years)	1 year 6 months
Trade name
Intangible Assets [Abstract]
Estimated useful lives (in years)	1 year
Developed software | Minimum
Intangible Assets [Abstract]
Estimated useful lives (in years)	2 years
Developed software | Maximum
Intangible Assets [Abstract]
Estimated useful lives (in years)	7 years