Leases (Supplemental Cash Flow Information) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 15,418
Operating cash flows from finance leases	123
Financing cash flows from finance leases	387
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	1,995
Finance leases	$ 3,796