Leases - Assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
Assets:
Operating lease right-of-use assets	$ 33,850	$ 27,270
Liabilities
Current portion of operating lease liabilities	10,625	9,192
Long-term operating lease liabilities	28,378	21,090
Total lease liabilities	39,003	30,282
Impairment of acceleration of remaining balance of ROU assets	4,903
ASU No. 2018-02, Leases (Topic 842)
Liabilities
Total lease liabilities	$ 39,003	$ 30,282