Accrued Expenses (Schedule of Accrued Expenses) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses [Abstract]
Salaries and benefits	$ 16,015	$ 13,506
Real estate and property taxes	7,928	7,125
Non-cash capital expenditures	12,387	12,408
Other	27,335	36,823
Total accrued expenses	$ 63,665	$ 69,862