Leases - Leasing Activities (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating Cash Flows for Finance Leases	$ 113
Operating Cash Flows for Operating Leases	31,643
Financing Cash Flows for Finance Leases	574
Total Cash Paid for Amounts Included in Measurement of Lease Liabilities	32,330
Right-of-Use Assets Obtained in Exchange for New Finance Lease Liabilities	0
Right-of-Use Assets Obtained in Exchange for New Operating Lease Liabilities	$ 6,587