Leases (Supplemental Cash Flow Information) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 21,345
Operating cash flows from finance leases	304
Financing cash flows from finance leases	775
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	3,992
Finance leases	$ 15,920