Leases - Assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets:
Operating lease right-of-use assets	$ 33,850
Liabilities
Current portion of operating leases	10,625
Long-term operating lease liabilities	28,378
Present value of lease liabilities	39,003
Impairment of acceleration of remaining balance of ROU assets	4,903
Operating Leases, Rent Expense, Net		$ 21,600	$ 17,100
ASU No. 2018-02, Leases (Topic 842)
Liabilities
Present value of lease liabilities	$ 39,003