Basis of Presentation (Components of Lease Cost, Lease Term, and Discount Rate) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Basis of Presentation [Abstract]
Amortization of right-of-use assets	$ 284		$ 621
Interest on finance lease liabilities	26		54
Total finance lease cost	310		675
Operating lease cost	66,523	$ 69,600	134,822	$ 137,600
Variable lease cost	9,424	$ 6,800	17,166	$ 13,600
Total lease cost	$ 76,257		$ 152,663
Weighted Average Remaining Lease Term: Operating leases	17 years 8 months 12 days		17 years 8 months 12 days
Weighted Average Remaining Lease Term: Finance leases	3 years 1 month 6 days		3 years 1 month 6 days
Weighted Average Discount Rate: Operating leases	6.10%		6.10%
Weighted Average Discount Rate: Finance leases	3.90%		3.90%
Cash paid for amounts included in measurement of lease liabilities: Cash flows from operating leases			$ 118,615
Cash paid for amounts included in measurement of lease liabilities: Cash flows from finance leases			$ 621