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]
Balance at Beginning of the Year	$ 6,898	$ 7,400	$ 7,761
Additions	5,774	5,479	4,983
Deductions	(5,340)	(5,981)	(5,344)
Balance at End of the Year	7,332	6,898	7,400
Allowance for Trade Receivable, Straight Line Rent [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of the Year	581	910	823
Additions	824	1,233	1,097
Deductions	(875)	(1,562)	(1,010)
Balance at End of the Year	530	581	910
Allowance for Trade Receivables [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of the Year	6,317	6,490	6,938
Additions	4,950	4,246	3,886
Deductions	(4,465)	(4,419)	(4,334)
Balance at End of the Year	$ 6,802	$ 6,317	$ 6,490