Acquisitions - Peak PACE Solutions (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Allocation of the purchase price based on the estimated fair values of the assets acquired and liabilities assumed
Revenue	$ 76,255		$ 48,598		$ 137,214	$ 92,542
Net income (loss)	(6,529)	$ (10,979)	(29,026)	$ (18,094)	(17,508)	(47,120)
Amortization expense	7,084		$ 2,639		11,751	$ 5,167
Peak PACE Solutions
Allocation of the purchase price based on the estimated fair values of the assets acquired and liabilities assumed
Revenue	2,184				4,397
Net income (loss)	137				308
Amortization expense	$ 181				$ 363