Equity - VIEs (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 54,466	$ 56,664
Accounts receivable	79,801	113,635
Other current assets	10,161	6,109
Total current assets	206,915	236,128
Goodwill	120,343	120,343
Other assets	4,924	5,647
Total assets	389,632	422,968
Current liabilities:
Accounts payable	34,654	48,245
Other current liabilities	1,741	1,697
Total current liabilities	137,588	141,955
Long-term liabilities:
Fair value of derivative liabilities	1,832	495
Long-term portion of Senior Credit Facility	95,000	123,000
Other long-term liabilities	197	217
Total liabilities	234,617	265,667
Variable Interest Entity, Primary Beneficiary
Current assets:
Cash and cash equivalents	54,196	56,598
Accounts receivable	79,801	113,635
Other current assets	69,419	64,476
Total current assets	203,416	234,709
Goodwill	120,343	120,343
Other assets	36,787	37,826
Total non-current assets	157,130	158,169
Total assets	360,546	392,878
Current liabilities:
Accounts payable	70,482	86,097
Other current liabilities	80,107	65,863
Total current liabilities	150,589	151,960
Long-term liabilities:
Long-term portion of Senior Credit Facility	95,000	123,000
Other long-term liabilities	2,029	712
Total long-term liabilities	97,029	123,712
Total liabilities	$ 247,618	$ 275,672