Leases - Supplemental balance sheet information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating lease liabilities	$ 116,652
Cash paid for amounts included in the measurement of lease liabilities within operating cash flows	12,636
Right of use assets obtained in exchange for operating lease obligations	$ 19,728
Weighted average remaining lease term	6 years 9 months 18 days
Weighted average discount rate	4.40%
Other current liabilities
Lessee, Lease, Description [Line Items]
Current operating lease liabilities	$ 20,100