Leases - Operating lease assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 17,688	$ 24,088
Current operating lease liabilities	10,603	10,099
Long-term operating lease liabilities	12,739	21,270
Total lease liabilities	$ 23,342	$ 31,369