Other Long-Term Liabilities (Schedule of Other Long-Term Liabilities) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Straight-line and deferred rent liabilities	$ 31,047,000	$ 31,016,000
Asset retirement obligations	4,691,000	4,580,000
Deferred compensation plan liability	9,475,000	9,319,000
Derivative Liability, Noncurrent	1,000	3,820,000
Total other long-term liabilities	$ 45,214,000	$ 48,735,000