Leases - Lease Balances within Condensed Consolidated Balance Sheet, Weighted Average Remaining Lease Term, and Weighted Average Discount Rates Related to Operating Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Assets:
Right-of-use assets from operating leases	$ 18,349	$ 22,500
Liabilities:
Operating lease liabilities - current	3,496
Operating lease liabilities - non-current	15,957
Total operating lease liabilities	$ 19,453	$ 22,500
Weighted average remaining lease term	4 years 9 months 7 days
Weighted average discount rate	6.60%