Equity Transactions Narrative (Details) - USD ($)						1 Months Ended						3 Months Ended								12 Months Ended
	Jan. 16, 2018	Jan. 02, 2018	Jun. 09, 2016	Mar. 30, 2016	Jun. 17, 2015	Nov. 30, 2017	Sep. 30, 2017	Jun. 30, 2017	May 31, 2017	Sep. 30, 2016	Jun. 30, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Nov. 30, 2004
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Shares						3,400,000
Stock Redeemed or Called During Period, Value						$ 85,500,000
Stock Issued During Period, Value, New Issues												$ 0		$ 0	$ 21,200,000	$ 1,500,000	$ 47,100,000	$ 34,400,000
New shares issued (in shares)				6,037,500					4,830,000	3,737,500		321,800,000		400,000,000	280,502	19,498	620,828	485,000	6,037,500
Share Price				$ 66.50															$ 66.50
Aggregate Value of Shares to be Issued in Accordance to Sales Agreement											$ 225,000,000									$ 450,000,000
Commission, Maximum Percentage of Gross Sales Price Per Share According to Sales Agreement																				2.00%
Shares Issued, Price Per Share									$ 86.00	$ 75.89							$ 75.89
Temporary Equity, Redemption Price Per Share												$ 25.00								$ 25.00
Temporary Equity, Redemption Price Per Share Including Accrued and Unpaid Dividends						$ 25.14349
Proceeds from issuance of common stock				$ 385,400,000					$ 408,900,000	$ 283,600,000									$ 385,400,000
Dividends per common share:																				$ 2.66	$ 2.60	$ 2.60
Cash, proceeds from dispositions held in escrow, or contingent liability								$ 2,000,000												$ 144,730,000	$ 89,700,000
Common Stock [Member]
Class of Stock [Line Items]
Dividends per common share:												0.67
Common Stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Payments of Ordinary Dividends, Common Stock	$ 55,225
Common OP Units [Member]
Class of Stock [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares					250,000,000			23,311
Series A-4 preferred OP units [Member]
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Shares													200,000
Series A-4 preferred stock [Member]
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Shares													438,448
Preferred Stock, Dividends Per Share, Declared												$ 0.40625
Series A-4 preferred stock [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Payments of Ordinary Dividends, Preferred Stock and Preference Stock		$ 441
Repurchase of Equity [Member] | Common Stock [Member]
Class of Stock [Line Items]
Authorized to be repurchased (in shares)																							1,000,000
Repurchase Agreements [Member] | Common Stock [Member]
Class of Stock [Line Items]
Remaining number of shares authorized to be repurchased (in shares)																400,000					400,000
Carefree Communities [Member]
Class of Stock [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares			3,329,880
Business Acquisition, Share Price			$ 67.57
Cash, proceeds from dispositions held in escrow, or contingent liability			$ 1,684,140,000
Green Courte [Member] | Series A-4 Preferred Stock and OP Units [Member]
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Value													$ 24,700,000
Payments of Dividends													$ 200,000
Pismo Dunes [Member]
Class of Stock [Line Items]
Cash, proceeds from dispositions held in escrow, or contingent liability							$ 26,400,000													$ 21,920,000
Pismo Dunes [Member] | Common OP Units [Member]
Class of Stock [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares							298,900
Series A-4 preferred OP units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				10,000,000	120,906,000
Series A-4 preferred OP units [Member] | Common OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				4,440,000	53,733,000
Conversion of Stock, Shares Issued																				444.4
Series A-4 preferred stock [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				158,036,000	385,242,000
Series A-4 preferred stock [Member] | Common OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				70,238,000	171,218,000
Conversion of Stock, Shares Issued																				444.4
Series A-1 Preferred OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				21,919,000	20,691,000
Series A-1 Preferred OP Units [Member] | Common OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				53,456,000	50,458,000
Conversion of Stock, Shares Issued																				2,439
Conversion of Common OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				36,055		104,106
Conversion of Common OP Units [Member] | Common OP Units [Member]
Class of Stock [Line Items]
Conversion of Common OP Units to common stock (in shares)																				36,055
Conversion of Stock, Shares Issued																				1,000