Schedule II: Valuation and Qualifying Accounts (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 Year	$ 114,964	$ 94,921	$ 70,411
Charged to Earnings	14,775	46,385	54,707
Acquired Properties	0	753	0
Uncollectible Accounts Written-off	(7,111)	(12,977)	(3,810)
Disposed Properties	(1,156)	(14,118)	(26,387)
Balance at End of Year	121,472	114,964	94,921
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	13,546	11,460	9,624
Charged to Earnings	5,093	10,937	8,204
Acquired Properties	0	753	0
Uncollectible Accounts Written-off	(7,111)	(12,977)	(4,272)
Disposed Properties	108	3,373	(2,096)
Balance at End of Year	11,636	13,546	11,460
Straight-line rent receivable allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	101,418	83,461	60,787
Charged to Earnings	9,682	35,448	46,503
Acquired Properties	0	0	0
Uncollectible Accounts Written-off	0	0	462
Disposed Properties	(1,264)	(17,491)	(24,291)
Balance at End of Year	$ 109,836	$ 101,418	$ 83,461