Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessee, Lease, Description [Line Items]
Operating and finance leases, renewal term		10 years
Operating and finance leases, options to terminate lease, term		1 year
Operating lease cost	$ 4,341	$ 8,589
Finance lease cost:
Amortization of right-of-use assets	1,357	2,732
Interest on lease liabilities	240	394
Total finance lease cost	$ 1,597	$ 3,126
Minimum
Lessee, Lease, Description [Line Items]
Operating and finance leases, remaining lease term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating and finance leases, remaining lease term		9 years