Lessee Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 3,600	$ 7,300
Cash paid for amounts included in the measurement of lease liabilities		7,391
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 557	$ 0
Weighted Average Remaining Lease Term (in years)	6 years 9 months 18 days	6 years 9 months 18 days
Weighted-average discount rate ( as a percent )	6.40%	6.40%