Leases - Supplemental Cash Flow Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Leases
Cash paid for operating lease liabilities	$ 20,307
Right-of-use assets obtained in exchange for new operating lease liabilities	6,180
Cash received from sublease income	$ 4,662
Weighted-average remaining lease term of operating leases	7 years 2 months 8 days
Weighted-average discount rate of operating leases	6.93%