Schedule II (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning balance	$ 1,472	$ 1,905	$ 2,551
Additions to allowance for doubtful accounts	2,546	2,565	2,613
Deductions to allowance for doubtful accounts	(2,597)	(2,998)	(3,259)
Allowance for doubtful accounts, ending balance	1,421	1,472	1,905
Allowance for Doubtful Accounts - Straight Line Rent [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning balance	257	316	601
Additions to allowance for doubtful accounts	1,501	1,412	1,271
Deductions to allowance for doubtful accounts	(1,066)	(1,471)	(1,556)
Allowance for doubtful accounts, ending balance	692	257	316
Allowance for Doubtful Accounts - Accounts Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning balance	928	1,314	1,648
Additions to allowance for doubtful accounts	1,045	1,141	1,342
Deductions to allowance for doubtful accounts	(1,349)	(1,527)	(1,676)
Allowance for doubtful accounts, ending balance	624	928	1,314
Allowance for Doubtful Accounts - Notes Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Allowance for doubtful accounts, beginning balance	287	275	302
Additions to allowance for doubtful accounts	0	12	0
Deductions to allowance for doubtful accounts	(182)	0	(27)
Allowance for doubtful accounts, ending balance	$ 105	$ 287	$ 275