Schedule II: Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 94,921	$ 70,411	$ 70,821
Charged to Earnings	46,385	54,707	49,011
Acquired Properties	753	0	0
Uncollectible Accounts Written-off	(12,977)	(3,810)	(7,265)
Disposed Properties	(14,118)	(26,387)	(42,156)
Balance at End of Year	114,964	94,921	70,411
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	11,460	9,624	11,090
Charged to Earnings	10,937	8,204	6,071
Acquired Properties	753	0	0
Uncollectible Accounts Written-off	(12,977)	(4,272)	(6,013)
Disposed Properties	3,373	(2,096)	(1,524)
Balance at End of Year	13,546	11,460	9,624
Straight-line rent receivable allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	83,461	60,787	59,731
Charged to Earnings	35,448	46,503	42,940
Acquired Properties	0	0	0
Uncollectible Accounts Written-off	0	462	(1,252)
Disposed Properties	(17,491)	(24,291)	(40,632)
Balance at End of Year	$ 101,418	$ 83,461	$ 60,787