Leases Leases - Supplemental Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Leases [Abstract]
Operating Lease, Payments	$ 12,877
Finance Lease, Interest Expense	5
Finance Lease, Principal Payments	12	$ 0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	9,551
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 5,227
Operating Lease, Weighted Average Remaining Lease Term	4 years 8 months 12 days
Finance Lease, Weighted Average Remaining Lease Term	7 years
Operating Lease, Weighted Average Discount Rate, Percent	3.70%
Finance Lease, Weighted Average Discount Rate, Percent	3.00%