Real Estate Acquisitions Real Estate Acquisitions, Narrative (Details)			1 Months Ended			3 Months Ended					9 Months Ended		12 Months Ended
	Jun. 09, 2016 USD ($) sites $ / shares shares	Mar. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) sites	May 31, 2017 USD ($) sites shares	Sep. 30, 2016 USD ($) shares	Sep. 30, 2017 USD ($) sites	Jun. 30, 2017 shares	Mar. 31, 2017 sites shares	Sep. 30, 2016 USD ($)	Mar. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) sites	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) sites manufactured_home states	Jul. 31, 2017 sites	Apr. 20, 2017 sites	Mar. 22, 2016 manufactured_home
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites													1,677
Proceeds from Issuance of Common Stock		$ 385,400,000		$ 408,900,000	$ 283,600,000					$ 385,400,000
New shares issued (in shares) | shares		6,037,500		4,830,000	3,737,500		400,000,000	280,502,000		6,037,500
Share Price | $ / shares		$ 66.50								$ 66.50
Transaction costs						$ 2,167,000			$ 4,191,000		$ 6,990,000	$ 27,891,000
Total consideration transferred			$ 26,400,000			$ 2,000,000					$ 92,752,000		$ 89,700,000
Number of States in which Entity Operates | states													6
Lazy J Ranch [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites			220			220					220
Total consideration transferred											$ 14,300,000
Ocean West [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites			130			130					130
Total consideration transferred											$ 9,673,000
Caliente Sands [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites			118			118					118
Total consideration transferred											$ 8,871,000
Arbor Woods [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites			458			458					458
Total consideration transferred											$ 16,943,000
Sunset Lakes [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites				498
Total consideration transferred											8,045,000
Pismo Dunes [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites														331
Total consideration transferred											21,920,000
Subsequent Land Acquisition [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites															775
Far Horizons 49er Village [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites								328
Total consideration transferred											$ 13,000,000
Bear Lake [Member]
Business Acquisition [Line Items]
Total consideration transferred									$ 5.9
Carefree Communities
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites	27,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares | shares	3,329,880
Business Acquisition, Share Price | $ / shares	$ 67.57
Cash, proceeds from prior dispositions held in escrow, or contingent liability	$ 225,000,000
Business Combination, Consideration Transferred, Pay Off of Debt	1,000,000,000
Total consideration transferred	$ 1,684,140,000
Manufactured Home And Rv Community [Member] | Carefree Communities
Business Acquisition [Line Items]
Number of Units in Real Estate Property | manufactured_home																103
RV community [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | manufactured_home													7
MH Community [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | manufactured_home													1