Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities:
Consolidated net income	$ 210,377	$ 187,132	$ 150,512
Adjustments to reconcile consolidated net income to net cash provided by operating activities:
Early debt retirement	2,785	0	16,913
Depreciation	122,720	118,521	114,698
Amortization of in-place leases	2,231	3,373	2,358
Amortization of loan costs	3,546	3,878	4,216
Debt premium amortization	(2,211)	(3,382)	(3,869)
Equity in income of unconsolidated joint ventures	(3,765)	(2,605)	(4,089)
Distributions of income from unconsolidated joint ventures	3,792	1,793	3,584
Stock-based compensation	9,352	9,181	8,582
Revenue recognized from right-to-use contract upfront payments	(10,020)	(9,248)	(8,552)
Commission expense recognized related to right-to-use contracts	4,509	4,149	3,595
Long term incentive plan compensation	1,347	(2,929)	973
(Recovery) provision for uncollectible rents receivable	(333)	(744)	537
Changes in assets and liabilities:
Notes receivable activity, net	(331)	318	66
Deferred commission expense	(4,577)	(4,659)	(5,871)
Escrow deposits, goodwill and other assets	45,401	23,706	44,095
Accrued expenses and accounts payable	(16,934)	10,322	5,632
Deferred revenue – upfront payments from right-to-use contracts	14,132	12,327	12,783
Deferred revenue – right-to-use annual payments	115	(61)	88
Rents received in advance and security deposits	2,354	2,276	6,631
Net cash provided by operating activities	384,490	353,348	352,882
Cash Flows From Investing Activities:
Real estate acquisition	(136,552)	(98,244)	(23,687)
Investment in unconsolidated joint ventures	(33,345)	(5,134)	(4,000)
Distributions of capital from unconsolidated joint ventures	0	4,094	80
Repayments of notes receivable	10,272	10,184	10,490
Issuance of notes receivable	(25,274)	(10,285)	(9,791)
Capital improvements	(126,050)	(119,437)	(93,799)
Net cash used in investing activities	(310,949)	(218,822)	(120,707)
Cash Flows From Financing Activities:
Proceeds from stock options and employee stock purchase plan	6,911	12,557	4,899
Gross proceeds from sale of Common Stock	120,698	50,000	0
Distributions:
Common Stockholders	(163,770)	(140,057)	(122,077)
Common OP Unitholders	(11,631)	(11,888)	(10,470)
Preferred Stockholders	(6,928)	(9,226)	(9,226)
Stock repurchase and Unit redemption	0	(229)	(62)
Share based award tax withholding payments	(3,087)	(2,423)	(3,139)
Principal payments and mortgage debt payoff	(270,530)	(142,731)	(456,308)
Mortgage notes payable financing proceeds	350,369	88,050	395,323
Line of Credit payoff	(101,000)	0	0
Line of Credit proceeds	131,000	0	0
Debt issuance and defeasance costs	(12,567)	(1,375)	(24,080)
Redemption of preferred stock	(136,314)	0	0
Other, primarily ATM offering costs	(1,947)	(1,122)	(491)
Net cash used in financing activities	(98,796)	(158,444)	(225,631)
Net (decrease) increase in cash and cash equivalents	(25,255)	(23,918)	6,544
Cash, beginning of year	56,340	80,258	73,714
Cash, end of year	31,085	56,340	80,258
Supplemental information:
Cash paid during the period for interest	102,570	105,556	106,423
Capital improvements – used homes acquired by repossessions	376	726	909
Net reduction of notes receivable – used homes acquired by repossessions	(376)	(726)	(909)
Building and other depreciable property – reclassification of rental homes	38,350	34,707	28,790
Escrow deposits and other assets – reclassification of rental homes	(38,350)	(34,707)	(28,790)
Real estate acquisitions:
Investment in real estate, fair value	(142,374)	(120,448)	(23,900)
Investment in real estate, cost	(110)	(2,000)	0
Escrow deposits and other assets	0	(20)	(53)
Debt assumed and financed on acquisition	5,900	22,010	0
Accrued expenses and accounts payable	32	1,883	62
Rents and other customer payments received in advance and security deposits	$ 0	$ 331	$ 204