Equity - VIEs (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 78,618	$ 56,664
Accounts receivable	68,043	113,635
Other current assets	7,623	6,109
Total current assets	201,524	236,128
Goodwill	120,343	120,343
Other assets	4,477	5,647
Total assets	372,012	422,968
Current liabilities:
Accounts payable	31,979	48,245
Other current liabilities	1,461	1,697
Total current liabilities	102,424	141,955
Long-term liabilities:
Long-term portion of Senior Credit Facility	100,000	123,000
Other long-term liabilities	73	217
Total liabilities	202,905	265,667
Variable Interest Entity, Primary Beneficiary
Current assets:
Cash and cash equivalents	78,149	56,598
Accounts receivable	68,043	113,635
Other current assets	53,006	64,476
Total current assets	199,198	234,709
Goodwill	120,343	120,343
Other assets	25,367	37,826
Total non-current assets	145,710	158,169
Total assets	344,908	392,878
Current liabilities:
Accounts payable	70,242	86,097
Other current liabilities	47,913	65,863
Total current liabilities	118,155	151,960
Long-term liabilities:
Long-term portion of Senior Credit Facility	100,000	123,000
Other long-term liabilities	481	712
Total long-term liabilities	100,481	123,712
Total liabilities	$ 218,636	$ 275,672