Leases - Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Operating leases:
Operating lease right-of-use assets, net	$ 53,923	$ 0
Accrued liabilities	13,706	0
Operating lease liabilities	43,365	$ 0
Total operating lease liabilities	$ 57,071