Property, Equipment and Capitalized Software - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 48,400	$ 36,800	$ 19,600
Capitalized software development costs	24,400	15,700	11,100
Amortization expense on capitalized software development costs	20,400	10,100	10,100
Capitalized compensation charges		40	90
Compensation costs, amortization	$ 20	$ 70	$ 700