Sun Communities (SUI) 10-Q 24 Apr 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 17, 2018
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	SUI
Entity Registrant Name	SUN COMMUNITIES INC
Entity Central Index Key	912,593
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		80,086,174

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Land	$ 1,114,609	$ 1,107,838
Land improvements and buildings	5,128,186	5,102,014
Rental homes and improvements	538,672	528,074
Furniture, fixtures and equipment	148,197	144,953
Investment property	6,929,664	6,882,879
Accumulated depreciation	(1,287,010)	(1,237,525)
Investment property, net (including $49,943 and $50,193 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	5,642,654	5,645,354
Cash and cash equivalents	15,153	10,127
Inventory of manufactured homes	36,311	30,430
Notes and other receivables, net	193,851	163,496
Collateralized receivables, net	123,155	128,246
Other assets, net (including $1,453 and $1,659 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	138,529	134,304
TOTAL ASSETS	6,149,653	6,111,957
LIABILITIES
Mortgage loans payable (including $41,756 and $41,970 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	2,826,225	2,867,356
Preferred OP units - mandatorily redeemable	37,338
Lines of credit		41,257
Distributions payable	58,663	55,225
Other liabilities (including $1,326 and $1,468 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	282,993	270,741
TOTAL LIABILITIES	3,471,096	3,405,204
Commitments and contingencies
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value. Authorized: 180,000 shares; Issued and outstanding: 79,885 shares at March 31, 2018 and 79,679 shares at December 31, 2017	799	797
Additional paid-in capital	3,759,066	3,758,533
Accumulated other comprehensive income (loss)	(670)	1,102
Distributions in excess of accumulated earnings	(1,187,563)	(1,162,001)
Total Sun Communities, Inc. stockholders' equity	2,571,632	2,598,431
Noncontrolling interests:
Common and preferred OP units	59,268	60,971
Consolidated variable interest entities	4,751	4,285
Total noncontrolling interests	64,019	65,256
TOTAL STOCKHOLDERS' EQUITY	2,635,651	2,663,687
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	6,149,653	6,111,957
Series A-4 Preferred Stock
LIABILITIES
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	32,414	32,414
Series A-4 preferred OP units
LIABILITIES
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	10,492	10,652
Aspen Series B3 Preferred Operating Partnership Units [Member]
LIABILITIES
Mortgage loans payable (including $41,756 and $41,970 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	37,338
Preferred OP units - mandatorily redeemable		41,443
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
LIABILITIES
Mortgage loans payable (including $41,756 and $41,970 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)		$ 129,182
Secured borrowings on collateralized receivables	124,077
Lines of credit	$ 141,800

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investment property, net	$ 5,642,654	$ 5,645,354
Other assets	138,529	134,304
Secured debt	2,826,225	2,867,356
Other liabilities	$ 282,993	$ 270,741
Series A Preferred Stock, Par Value	$ 0.01	$ 0.01
Series A Preferred Stock, Shares Issued	3,400	3,400
Series A Preferred Stock, Shares Outstanding	3,400	3,400
Common Stock, Par Value	$ 0.01	$ 0.01
Common Stock, Shares Authorized	180,000	180,000
Common Stock, Shares Issued	79,341	73,206
Common Stock, Shares Outstanding	79,341	73,206
Series A-4 Preferred Stock
Series A-4 Preferred Stock, Par Value	$ 0.01	$ 0.01
Series A-4 Preferred Stock, Shares Issued	1,085	1,681
Series A-4 Preferred Stock, Shares Outstanding	1,085	1,681
Variable Interest Entity, Primary Beneficiary [Member]
Investment property, net	$ 49,943	$ 50,193
Other assets	1,453	1,659
Secured debt	41,756	41,970
Other liabilities	$ 1,326	$ 1,468

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
REVENUES
Income from real property	$ 197,211	$ 183,054
Revenue from home sales	34,900	27,263
Rental home revenue	13,020	12,339
Ancillary revenues	6,568	6,219
Interest	5,316	4,646
Brokerage commissions and other revenues, net	901	879
Total revenues	257,916	234,400
EXPENSES
Property operating and maintenance	51,630	47,166
Real estate taxes	13,836	13,143
Cost of home sales	26,571	20,883
Rental home operating and maintenance	5,170	5,102
Ancillary expenses	5,266	4,668
Home selling expenses	3,290	3,111
General and administrative	19,931	17,932
Transaction costs	0	2,386
Depreciation and amortization	66,437	62,766
Loss on extinguishment of debt	196	466
Interest	31,138	31,322
Interest on mandatorily redeemable preferred OP units	619	784
Total expenses	221,871	209,816
Income before other items	36,045	24,584
Catastrophic weather related charges	2,213	87
Other (expense) / income, net	(2,617)	839
Current tax expense	(174)
Provision for state income taxes	200	(178)
Deferred tax benefit	347	300
Net income	33,601	25,545
Less: Preferred return to preferred OP units	(1,080)	(1,174)
Less: Amounts attributable to noncontrolling interests	(2,094)	(1,088)
Net income attributable to Sun Communities, Inc.	30,427	23,283
Less: Preferred stock distributions	(441)	(2,179)
Net income attributable to Sun Communities, Inc. common stockholders	$ 29,986	$ 21,104
Weighted average common shares outstanding:
Basic	78,855	72,677
Diluted	79,464	73,120
Earnings per share:
Basic	$ 0.38	$ 0.29
Diluted	$ 0.38	$ 0.29

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 33,601	$ 25,545
Foreign currency translation adjustment	(1,861)	584
Total comprehensive income	31,740	26,129
Less: Comprehensive income attributable to noncontrolling interests	2,005	1,121
Comprehensive income attributable to Sun Communities, Inc.	$ 29,735	$ 25,008

Consolidated Statement Of Stock

Consolidated Statement Of Stockholders' Equity - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Distributions in Excess of Accumulated Earnings	Accumulated Other Comprehensive Income / (Loss)	Noncontrolling Interests
Balance at Dec. 31, 2017	$ 2,663,687	$ 797	$ 3,758,533	$ (1,162,001)	$ 1,102	$ 65,256
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation - issuances net of amortization and forfeitures	283	2	191	90
Conversion of OP units	59	0	342			(283)
Foreign currency translation	(1,861)				(1,772)	(89)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest and Returns from Preferred Stock	33,530			31,507		2,023
Distributions	(60,047)			(57,159)		(2,888)
Balance at Mar. 31, 2018	$ 2,635,651	$ 799	$ 3,759,066	$ (1,187,563)	$ (670)	$ 64,019

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING ACTIVITIES:
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 80,905	$ 69,208
INVESTING ACTIVITIES:
Investment in properties	(68,524)	(61,431)
Acquisitions of properties, net of cash acquired	(2,384)	(13,000)
Proceeds from dispositions of assets and depreciated homes, net	5,312	2,898
Purchases of notes receivable	(893)	(447)
Repayments of notes and other receivables	679	317
Payments for (Proceeds from) Other Investing Activities	(2,708)	0
NET CASH USED FOR INVESTING ACTIVITIES	(68,518)	(71,663)
FINANCING ACTIVITIES:
Issuance and costs of common stock, OP units, and preferred OP units, net	(3,296)	20,549
Borrowings on lines of credit	302,355	235,454
Payments on lines of credit	(201,853)	(157,237)
Proceeds from issuance of other debt	0	3,108
Payments on other debt	(38,883)	(42,296)
Prepayment penalty on debt	(196)	(466)
Distributions to stockholders, OP unit holders, and preferred OP unit holders	(56,881)	(53,447)
Payments for deferred financing costs	(605)	(1,803)
Proceeds from (Payments for) Other Financing Activities	(5,000)	0
NET CASH PROVIDED BY FINANCING ACTIVITIES	(8,464)	3,862
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(8)	(10)
Net change in cash, cash equivalents and restricted cash	3,915	1,397
Cash, cash equivalents and restricted cash, beginning of period	23,509	25,313
Cash, cash equivalents and restricted cash, end of period	27,424	26,710
SUPPLEMENTAL INFORMATION:
Cash paid for interest (net of capitalized interest of $1,184 and $638 respectively)	30,402	30,637
Cash paid for interest on mandatorily redeemable debt	619	784
Cash paid for income taxes	135	116
Noncash investing and financing activities:
Reduction in secured borrowing balance	5,105	5,914
Change in distributions declared and outstanding	3,337	859
Conversion of common and preferred OP units	342	959
Conversion of Series A-4 Preferred Stock	0	1,348
Series B-3 Preferred OP Units [Member]
FINANCING ACTIVITIES:
Redemption of Series A-4 preferred stock and OP units	$ (4,105)	$ 0

Consolidated Statements Of Cas8

Consolidated Statements Of Cash Flows (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
Capitalized interest	$ 1,981	$ 378

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Sun Communities, Inc., a Maryland corporation, and all wholly-owned or majority-owned and controlled subsidiaries, including Sun Communities Operating Limited Partnership (the “Operating Partnership”) and Sun Home Services, Inc. (“SHS”) are referred to herein as the “Company,” “us,” “we,” and “our.” We follow accounting standards set by the Financial Accounting Standards Board (“FASB”). FASB sets generally accepted accounting principles (“GAAP”), which we follow to ensure that we consistently report our financial condition, results of operations, and cash flows. References to GAAP issued by the FASB in these footnotes are to the FASB Accounting Standards Codification (“ASC”). These unaudited Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial information and in accordance with GAAP. Pursuant to the SEC rules and regulations we present interim disclosures and certain information and footnote disclosures as required. Accordingly, the unaudited Consolidated Financial Statements do not include all of the information and footnotes required by GAAP for complete financial statements. The accompanying unaudited Consolidated Financial Statements reflect, in the opinion of management, all adjustments, including adjustments of a normal and recurring nature, necessary for a fair presentation of the interim financial statements. All intercompany transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period financial statements in order to conform to current period presentation. The results of operations for interim periods are not necessarily indicative of results that may be expected for any other interim period or for the full year. These unaudited Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017 as filed with the SEC on February 22, 2018 (the “ 2017 Annual Report”). These statements have been prepared on a basis that is substantially consistent with the accounting principles applied in our 2017 Annual Report.

Revenue

Revenue	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue The following table disaggregates our revenue by major source (in thousands): Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated REVENUE Income from real property $ 197,211 $ — $ 197,211 $ 183,054 $ — $ 183,054 Revenue from home sales — 34,900 34,900 — 27,263 27,263 Rental home revenue — 13,020 13,020 — 12,339 12,339 Ancillary revenues 6,568 — 6,568 6,219 — 6,219 Interest 5,316 — 5,316 4,646 — 4,646 Brokerage commissions and other revenues, net 960 (59 ) 901 879 — 879 Total revenue $ 210,055 $ 47,861 $ 257,916 $ 194,798 $ 39,602 $ 234,400 Revenue Recognition Policies and Performance Obligations On January 1, 2018, we adopted FASB Accounting Standards Update (“ASU”) 2014-09 “Revenue from Contracts with Customers” and the other related ASUs and amendments to the codification (collectively “ASC 606”). The core principle of ASC 606 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. A five-step transactional analysis is required to determine how and when to recognize revenue. ASC 606 applies to all contracts with customers, except those that are within the scope of other topics in the FASB accounting standards codification. As a real estate owner and operator, the majority of our revenue is derived from site and home leases that are accounted for pursuant to ASC 840 “Leases.” For transactions in the scope of ASC 606, we recognize revenue when control of goods or services transfers to the customer, in the amount that we expect to receive for the transfer of goods or provision of services. The adoption of ASC 606 did not result in any change to our accounting policies for revenue recognition. Accordingly, retrospective application to prior periods or a cumulative catch-up adjustment was unnecessary. Income from real property - Residents in our communities lease the site on which their home is located, and either own or lease their home. Lease revenues for sites and homes fall under the scope of ASC 840, and are accounted for as operating leases with straight-line recognition. Resident leases are generally for one-year or month-to-month terms, and are renewable by mutual agreement from us and the resident, or in some cases, as provided by jurisdictional statute. Non-lease components of our site lease contracts, which are primarily provision of utility services, are accounted for with the site lease as a single lease under ASC 840. Additionally, we include collections of real estate taxes from residents within Income from real property. Revenue from home sales - Our taxable REIT subsidiary, SHS, sells manufactured homes (“MH”) to current and prospective residents in our communities. Prior to adoption of ASC 606, we recognized revenue for home sales pursuant to ASC 605 “Revenue Recognition,” as manufactured homes are tangible personal property that can be located on any land parcel. Manufactured homes are not permanent fixtures or improvements to the underlying real estate, and were therefore not considered to be subject to the guidance in ASC 360-20 “Real Estate Sales” by the Company. In accordance with the core principle of ASC 606, we recognize revenue from home sales at the time of closing when control of the home transfers to the customer. After closing of the sale transaction, we have no remaining performance obligation. Rental home revenue - is comprised of rental agreements whereby we lease homes to residents in our communities. We account for these revenues under ASC 840. Ancillary revenues - are primarily composed of proceeds from restaurant, golf, merchandise and other activities at our RV communities. Revenues are recognized at point of sale when control of the good or service transfers to the customer and our performance obligation is satisfied. Sales and other taxes that we collect concurrent with revenue-producing activities are excluded from transaction price. Interest income - is earned primarily on our notes and collateralized receivables, which includes installment loans for manufactured homes purchased by the Company from loan originators and transferred loans that previously did not meet the requirements for sale accounting. Interest income on these receivables is accrued based on the unpaid principal balances of the underlying loans on a level yield basis over the life of the loans. Interest income is not in the scope of ASC 606. Refer to notes 4 , “Collateralized Receivables and Transfers of Financial Assets” and 5 , “Notes and Other Receivables” for additional information. Broker commissions and other revenues, net - is primarily comprised of brokerage commissions for sales of manufactured homes, where we act as agent and arrange for a third party to transfer a manufactured home to a customer within one of our communities. Brokerage commission revenues are recognized on a net basis at closing, when the transaction is completed and our performance obligations have been fulfilled. Loan loss reserve expenses for our collateralized receivables and notes receivables are also included herein. Refer to notes 4 , “Collateralized Receivables and Transfers of Financial Assets” and 5 , “Notes and Other Receivables” for additional information regarding our loan loss reserves. Contract Balances As of March 31, 2018 and December 31, 2017, we had $28.6 million and $13.8 million respectively of receivables from contracts with customers. Receivables from contracts with customers are presented as a component of Notes and other receivables on our Consolidated Balance Sheets. These receivables represent balances owed to us for previously completed performance obligations for sales of manufactured homes. Due to the nature of our revenue from contacts with customers, we do not have material contract assets or liabilities that fall under the scope of ASC 606.

Real Estate Acquisitions

Real Estate Acquisitions	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Real Estate Acquisitions	Real Estate Acquisitions 2018 Acquisitions There were no community acquisitions during the three months ended March 31, 2018 . 2017 Acquisitions In December 2017, we acquired Colony in the Wood (“Colony in the Wood”), an age-restricted MH community with 383 sites located in Port Orange, Florida. In November 2017, we acquired Emerald Coast RV Beach Resort (“Emerald Coast”), an MH and recreational vehicle (“RV”) community with 201 sites located in Panama City Beach, Florida. In September 2017, we acquired three age-restricted MH communities: Lazy J Ranch (“Lazy J Ranch”), with 220 sites in Arcata, California; Ocean West (“Ocean West”), with 130 sites in McKinleyville, California; and Caliente Sands (“Caliente Sands”), with 118 sites in Cathedral City, California. In July 2017, we acquired Pismo Dunes RV Resort (“Pismo Dunes”), an age-restricted RV community with 331 sites located in Pismo Beach, California. In June 2017, we acquired Arbor Woods (“Arbor Woods”), a MH community with 458 sites located in Superior Township, Michigan. In May 2017, we acquired Sunset Lakes RV Resort (“Sunset Lakes”), a RV resort with 498 sites located in Hillsdale, Illinois. In March 2017, we acquired Far Horizons 49er Village RV Resort Inc. (“49er Village”), a RV resort with 328 sites located in Plymouth, California. The following table summarizes the amounts of assets acquired net of liabilities assumed at the acquisition date and the consideration paid for the acquisitions completed in 2017 (in thousands): At Acquisition Date Colony in the Wood Emerald Coast Lazy J Ranch Ocean West Caliente Sands Pismo Dunes Arbor Woods Sunset Lakes 49er Village Total Investment in property $ 31,818 $ 19,400 $ 13,938 $ 9,453 $ 8,640 $ 21,260 $ 15,725 $ 7,835 $ 12,890 $ 140,959 Notes receivable — — — — — — 23 — — 23 Inventory of manufactured homes — — 2 — 21 — 465 — — 488 In-place leases and other tangible assets 660 100 360 220 210 660 730 210 110 3,260 Total identifiable assets acquired net of liabilities assumed $ 32,478 $ 19,500 $ 14,300 $ 9,673 $ 8,871 $ 21,920 $ 16,943 $ 8,045 $ 13,000 $ 144,730 Consideration Cash $ 32,478 $ 19,500 $ 14,300 $ 5,081 $ 8,871 $ — $ 14,943 $ 8,045 $ 13,000 116,218 Equity — — — — — 26,410 2,000 — — 28,410 Liabilities assumed — — — 4,592 — 510 — — — 5,102 Cash proceeds from seller — — — — — (5,000 ) — — — (5,000 ) Total consideration $ 32,478 $ 19,500 $ 14,300 $ 9,673 $ 8,871 $ 21,920 $ 16,943 $ 8,045 $ 13,000 $ 144,730 Also in 2017, we acquired an undeveloped parcel of land, on which we will construct Carolina Pines RV Resort (“Carolina Pines” formerly known as Bear Lake), near Myrtle Beach, South Carolina, for $5.9 million. This land parcel has been entitled and zoned to build an 841 site RV resort. Transaction costs of $2.4 million were incurred for the three months ended March 31, 2017. These costs are presented as Transaction costs in our Consolidated Statements of Operations. Beginning January 1, 2018, we expect that substantially all of our property acquisitions will be considered asset acquisitions. Accordingly, direct acquisition related costs will be capitalized as part of the purchase price. Acquisitions costs that do not meet the criteria for capitalization will be expensed as incurred and presented as General and administrative costs in our Consolidated Statements of Operations. Refer to Note 16 , “Recent Accounting Pronouncements,” for additional information. Dispositions There were no property dispositions during the three months ended March 31, 2018 or the year ended December 31, 2017.

Collateralized Receivables and

Collateralized Receivables and Transfers of Financial Assets	3 Months Ended
	Mar. 31, 2018
Transfers and Servicing [Abstract]
Transfers Of Financial Assets	Transfers of Financial Assets We previously completed various transactions with an unrelated entity involving our notes receivable under which we received cash proceeds in exchange for relinquishing our right, title, and interest in certain notes receivable. We have no further obligations or rights with respect to the control, management, administration, servicing, or collection of the installment notes receivable. However, we are subject to certain recourse provisions requiring us to purchase the underlying homes collateralizing such notes, in the event of a note default and subsequent repossession of the home by the unrelated entity. The recourse provisions are considered to be a form of continuing involvement, and therefore these transferred loans did not meet the requirements for sale accounting. We continue to recognize these transferred loans on our balance sheet and refer to them as collateralized receivables. The proceeds from the transfer have been recognized as a secured borrowing. In the event of a note default and subsequent repossession of a manufactured home by the unrelated entity, the terms of the agreement require us to repurchase the manufactured home. Default is defined as the failure to repay the installment note receivable according to contractual terms. The repurchase price is calculated as a percentage of the outstanding principal balance of the collateralized receivable, plus any outstanding late fees, accrued interest, legal fees, and escrow advances associated with the installment note receivable. The percentage used to determine the repurchase price of the outstanding principal balance on the installment note receivable is based on the number of payments made on the note. In general, the repurchase price is determined as follows: Number of Payments Repurchase Percentage Fewer than or equal to 15 100 % Greater than 15 but fewer than 64 90 % Equal to or greater than 64 but fewer than 120 65 % 120 or more 50 % The transferred assets have been classified as Collateralized receivables, net and the cash proceeds received from these transactions have been classified as Secured borrowings on collateralized receivables within the Consolidated Balance Sheets. The balance of the collateralized receivables was $123.2 million (net of allowance of $0.9 million ) and $128.2 million (net of allowance of $0.9 million ) as of March 31, 2018 and December 31, 2017 , respectively. The receivables have a weighted average interest rate and maturity of 10.0 percent and 15.1 years as of March 31, 2018 , and 10.0 percent and 15.3 years as of December 31, 2017 . The outstanding balance on the secured borrowing was $124.1 million and $129.2 million as of March 31, 2018 and December 31, 2017 , respectively. The collateralized receivables earn interest income, and the secured borrowings accrue interest expense at the same interest rates. The amount of interest income and expense recognized was $2.8 million and $3.3 million for the three months ended March 31, 2018 and 2017 , respectively. The balances of the collateralized receivables and secured borrowings fluctuate. The balances increase as additional notes receivable are transferred and exchanged for cash proceeds. The balances are reduced as the related collateralized receivables are collected from the customers, or as the underlying collateral is repurchased. The change in the aggregate gross principal balance of the collateralized receivables is as follows (in thousands): Three Months Ended March 31, 2018 Beginning balance $ 129,182 Principal payments and payoffs from our customers (2,557 ) Principal reduction from repurchased homes (2,548 ) Total activity (5,105 ) Ending balance $ 124,077 The following table sets forth the allowance for the collateralized receivables as of March 31, 2018 (in thousands): Three Months Ended March 31, 2018 Beginning balance $ (936 ) Lower of cost or market write-downs 313 Increase to reserve balance (299 ) Total activity 14 Ending balance $ (922 )

Notes And Other Receivables

Notes And Other Receivables	3 Months Ended
	Mar. 31, 2018
Long-term Notes and Loans, by Type, Current and Noncurrent [Abstract]
Notes And Other Receivables	Notes and Other Receivables The following table sets forth certain information regarding notes and other receivables (in thousands): March 31, 2018 December 31, 2017 Installment notes receivable on manufactured homes, net $ 124,738 $ 115,797 Other receivables, net 69,113 47,699 Total notes and other receivables, net $ 193,851 $ 163,496 Installment Notes Receivable on Manufactured Homes The installment notes of $124.7 million (net of allowance of $0.4 million ) and $115.8 million (net of allowance of $0.4 million ) as of March 31, 2018 and December 31, 2017 , respectively, are collateralized by manufactured homes. The notes represent financing provided by us to purchasers of manufactured homes primarily located in our communities and require monthly principal and interest payments. The notes have a net weighted average interest rate (net of servicing costs) and maturity of 8.0 percent and 17.2 years as of March 31, 2018 , and 8.2 percent and 17.2 years as of December 31, 2017 , respectively. The change in the aggregate gross principal balance of the installment notes receivable is as follows (in thousands): Three Months Ended March 31, 2018 Beginning balance $ 116,174 Financed sales of manufactured homes 12,842 Principal payments and payoffs from our customers (1,912 ) Principal reduction from repossessed homes (1,935 ) Total activity 8,995 Ending balance $ 125,169 Allowance for Losses for Installment Notes Receivable The following table sets forth the allowance change for the installment notes receivable as follows (in thousands): Three Months Ended March 31, 2018 Beginning balance $ (377 ) Lower of cost or market write-downs 175 Increase to reserve balance (229 ) Total activity (54 ) Ending balance $ (431 ) Other Receivables As of March 31, 2018 , other receivables were comprised of amounts due from: residents for rent, and water and sewer usage of $12.5 million (net of allowance of $1.2 million ); home sale proceeds of $28.6 million ; and insurance and other receivables of $28.0 million . As of December 31, 2017 , other receivables were comprised of amounts due from: residents for rent, and water and sewer usage of $7.0 million (net of allowance of $1.5 million ); home sale proceeds of $13.8 million ; and insurance and other receivables of $26.9 million .

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	Intangible Assets Our intangible assets include ground leases, in-place leases, franchise fees and other intangible assets. These intangible assets are recorded in Other assets, net on the Consolidated Balance Sheets. The gross carrying amounts, and accumulated amortization are as follows (in thousands): March 31, 2018 December 31, 2017 Intangible Asset Useful Life Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Ground leases 8-57 years $ 32,165 $ (1,632 ) $ 32,165 $ (1,409 ) In-place leases 7 years 101,365 (49,066 ) 100,843 (45,576 ) Franchise fees and other intangible assets 15 years 1,880 (1,470 ) 1,880 (1,451 ) Total $ 135,410 $ (52,168 ) $ 134,888 $ (48,436 ) Total amortization expenses related to the intangible assets are as follows (in thousands): Three Months Ended Intangible Asset 2018 2017 2016 Ground leases $ 223 $ 257 $ — In-place leases 3,490 3,416 2,153 Franchise fees and other intangible assets 19 129 129 Total $ 3,732 $ 3,802 $ 2,282 We anticipate amortization expense for our intangible assets to be as follows for the next five years (in thousands): Year Remainder of 2018 2019 2020 2021 2022 Estimated expense $ 10,786 $ 13,685 $ 11,957 $ 11,565 $ 6,964

Consolidated Variable Interest

Consolidated Variable Interest Entities	3 Months Ended
	Mar. 31, 2018
DisclosureofVariableInterestEntities [Abstract]
Consolidated Variable Interest Entities	Consolidated Variable Interest Entities We consolidate Rudgate Village SPE, LLC; Rudgate Clinton SPE, LLC; and Rudgate Clinton Estates SPE, LLC (collectively, “Rudgate”) as a variable interest entity (“VIE”). We evaluated our arrangement with this property under the guidance set forth in FASB ASC Topic 810 “ Consolidation. ” We concluded that Rudgate qualified as a VIE where we are the primary beneficiary, as we have power to direct the significant activities, absorb the significant losses and receive the significant benefits from the entity. The following table summarizes the assets and liabilities included in our Consolidated Balance Sheets after eliminations (in thousands): March 31, 2018 December 31, 2017 ASSETS Investment property, net $ 49,943 $ 50,193 Other assets 1,453 1,659 Total Assets $ 51,396 $ 51,852 LIABILITIES AND STOCKHOLDERS’ EQUITY Debt $ 41,756 $ 41,970 Other liabilities 1,326 1,468 Noncontrolling interests 4,751 4,285 Total Liabilities and Stockholders’ Equity $ 47,833 $ 47,723 Investment property, net and other assets related to the consolidated VIEs comprised approximately 0.8 percent of our consolidated total assets at March 31, 2018 and December 31, 2017 . Debt and other liabilities comprised approximately 1.2 percent of our consolidated total liabilities at March 31, 2018 and December 31, 2017 . Noncontrolling interests related to the consolidated VIEs, on an absolute basis, comprised less than 1.0 percent of our consolidated total equity at March 31, 2018 and at December 31, 2017 .

Debt And Lines Of Credit

Debt And Lines Of Credit	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Debt and Lines of Credit The following table sets forth certain information regarding debt including premiums, discounts and deferred financing costs (in thousands): Carrying Amount Weighted Average Years to Maturity Weighted Average Interest Rates March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 Collateralized term loans - Life Companies $ 1,038,459 $ 1,044,246 13.7 13.9 3.9 % 3.9 % Collateralized term loans - FNMA 994,605 1,026,014 5.5 5.6 4.4 % 4.4 % Collateralized term loans - CMBS 408,251 410,747 4.8 5.0 5.1 % 5.1 % Collateralized term loans - FMCC 384,910 386,349 6.6 6.9 3.9 % 3.9 % Secured borrowings 124,077 129,182 15.1 15.3 10.0 % 10.0 % Lines of credit 141,800 41,257 3.0 3.1 3.0 % 2.8 % Preferred OP units - mandatorily redeemable 37,338 41,443 5.4 5.0 6.6 % 6.7 % Total debt $ 3,129,440 $ 3,079,238 8.5 8.9 4.5 % 4.5 % Collateralized Term Loans During the three months ended March 31, 2018, we repaid four collateralized term loans totaling $24.4 million with a weighted average interest rate of 6.36 percent , releasing three encumbered communities. The loans were due to mature on March 1, 2019. We recognized a loss on extinguishment of debt of $0.2 million as a result of the repayment transactions. In December 2017, we defeased a $38.6 million collateralized term loan with a 5.25 percent fixed interest rate that was due to mature on June 1, 2022. As a result of the transaction we recognized a loss on extinguishment of debt of $5.2 million in our Consolidated Statements of Operations. Concurrent with the defeasance, we entered into a new $100.0 million collateralized term loan, encumbered by the same property, with a 4.25 percent fixed rate of interest and 30 -year term. In September 2017, in connection with the Ocean West acquisition, we assumed a $4.6 million collateralized term loan with Fannie Mae, with an interest rate of 4.34 percent and a remaining term of 9.8 years. In June 2017, we entered into a $77.0 million collateralized term loan which bears interest at a rate of 4.16 percent amortizing over a 25 -year term. We also repaid a $3.9 million collateralized term loan with an interest rate of 6.54 percent that was due to mature on August 31, 2017. As a result of the repayment transaction, we recognized a loss on extinguishment of debt of $0.3 million in our Consolidated Statements of Operations. During the first quarter of 2017, we defeased an $18.9 million collateralized term loan with an interest rate of 6.49 percent that was due to mature on August 1, 2017, releasing one encumbered community. As a result of the transaction, we recognized a loss on extinguishment of debt of $0.5 million in our Consolidated Statements of Operations. In addition, we repaid a $10.0 million collateralized term loan with an interest rate of 5.57 percent that was due to mature on May 1, 2017, releasing an additional encumbered community. The collateralized term loans totaling $2.8 billion as of March 31, 2018 , are secured by 187 properties comprised of 74,630 sites representing approximately $3.3 billion of net book value. Secured Borrowing See Note 4 , “Collateralized Receivables and Transfers of Financial Assets,” for information regarding our collateralized receivables and secured borrowing transactions. Preferred OP Units Preferred OP units at March 31, 2018 and December 31, 2017 include $34.7 million of Aspen preferred OP units issued by the Operating Partnership. As of March 31, 2018 , these units are convertible indirectly into 463,652 shares of our common stock. Subject to certain limitations, at any time prior to January 1, 2024, the holder of each Aspen preferred OP unit at its option may convert such Aspen preferred OP unit into: (a) if the market price of our common stock is $68.00 per share or less, 0.397 common OP units; or (b) if the market price of our common stock is greater than $68.00 per share, the number of common OP units is determined by dividing (i) the sum of (A) $27.00 plus (B) 25 percent of the amount by which the market price of our common stock exceeds $68.00 per share, by (ii) the per-share market price of our common stock. The current preferred distribution rate is 6.5 percent . On January 2, 2024, we are required to redeem all Aspen preferred OP units that have not been converted to common OP units. Preferred OP units also include $2.7 million and $6.7 million at March 31, 2018 and December 31, 2017 , respectively, of Series B-3 preferred OP units, which are not convertible. During the three months ended March 31, 2018 , we redeemed 41,051 of the Series B-3 preferred OP units at an average redemption price per unit, which included accrued and unpaid distributions, of $100.065753 . In the aggregate, we paid $4.1 million to redeem these units. Subject to certain limitations, (a) during the 90 -day period beginning on each of the tenth through fifteenth anniversaries of the issue date of the applicable Series B-3 preferred OP units, (b) at any time after the fifteenth anniversary of the issue date of the applicable Series B-3 preferred OP units, or (c) after our receipt of notice of the death of the electing holder of a Series B-3 preferred OP unit, each holder of Series B-3 preferred OP units may require us to redeem such holder's Series B-3 preferred OP units at the redemption price of $100.00 per unit. In addition, at any time after the fifteenth anniversary of the issue date of the applicable Series B-3 preferred OP units we may redeem, at our option, all of the Series B-3 preferred OP units of any holder thereof at the redemption price of $100.00 per unit. Lines of Credit In April 2017, we amended and restated our credit agreement (the “A&R Credit Agreement”) with Citibank, N.A. (“Citibank”) and certain other lenders. Pursuant to the A&R Credit Agreement, we have a senior revolving credit facility with Citibank and certain other lenders in the amount of $650.0 million , comprised of a $550.0 million revolving loan and a $100.0 million term loan (the “A&R Facility”). The A&R Credit Agreement has a four -year term ending April 25, 2021 , which can be extended for two additional six -month periods at our option, subject to the satisfaction of certain conditions as defined in the credit agreement. The A&R Credit Agreement also provides for, subject to the satisfaction of certain conditions, additional commitments in an amount not to exceed $350.0 million . If additional borrowings are made pursuant to any such additional commitments, the aggregate borrowing limit under the Facility may be increased up to $1.0 billion . The A&R Facility bears interest at a floating rate based on the Eurodollar rate plus a margin that is determined based on our leverage ratio calculated in accordance with the A&R Credit Agreement, which margin can range from 1.35 percent to 2.20 percent for the revolving loan and 1.30 percent to 2.15 percent for the term loan. As of March 31, 2018 , the margin on our leverage ratio was 1.35 percent and 1.30 percent on the revolving and term loans, respectively. We had $40.0 million in borrowings on the revolving loan and $100.0 million in borrowings on the term loan, totaling $140.0 million as of March 31, 2018 , with a weighted average interest rate of 3.0 percent . The A&R Facility replaced our $450.0 million credit facility (the “Previous Facility”), which was scheduled to mature on August 19, 2019. The A&R Facility provides, and the Previous Facility provided, us with the ability to issue letters of credit. Our issuance of letters of credit does not increase our borrowings outstanding under our line of credit, but does reduce the borrowing amount available. At March 31, 2018 and December 31, 2017 , approximately $1.3 million of availability was used to back standby letters of credit. We have a $12.0 million manufactured home floor plan facility renewable indefinitely until our lender provides us at least a twelve month notice of their intent to terminate the agreement. The interest rate is 100 basis points over the greater of the prime rate as quoted in the Wall Street Journal on the first business day of each month or 6.0 percent. At March 31, 2018 , the effective interest rate was 7.0 percent . The outstanding balance was $2.3 million as of March 31, 2018 and $4.0 million as of December 31, 2017 . Covenants Pursuant to the terms of the A&R Facility, we are subject to various financial and other covenants. The most restrictive of our debt agreements place limitations on secured borrowings and contain minimum fixed charge coverage, leverage, distribution, and net worth requirements. At March 31, 2018 , we were in compliance with all covenants. In addition, certain of our subsidiary borrowers own properties that secure loans. These subsidiaries are consolidated within our accompanying Consolidated Financial Statements, however, each of these subsidiaries’ assets and credit are not available to satisfy the debts and other obligations of the Company, any of its other subsidiaries or any other person or entity.

Equity and Mezzanine Securities

Equity and Mezzanine Securities	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Equity and Mezzanine Securities	Equity and Mezzanine Securities Public Equity Offerings In May 2017, we closed an underwritten registered public offering of 4,830,000 shares of common stock at a gross price of $86.00 per share. Proceeds from the offering were $408.9 million after deducting expenses related to the offering, which were used to repay borrowings outstanding under the revolving loan under our A&R Facility, fund acquisitions, working capital and general corporate purposes. At the Market Offering Sales Agreement In July 2017, we entered into a new at the market offering sales agreement (the “Sales Agreement”) with BMO Capital Markets Corp., Merrill Lynch, Pierce, Fenner & Smith Incorporated, Citigroup Global Markets Inc., Robert W. Baird & Co. Incorporated, Fifth Third Securities, Inc., RBC Capital Markets, LLC, BTIG, LLC, Jefferies LLC, Credit Suisse Securities (USA) LLC and Samuel A. Ramirez & Company, Inc. (each, a “Sales Agent;” collectively, the “Sales Agents”), whereby we may offer and sell shares of our common stock, having an aggregate offering price of up to $450.0 million , from time to time through the Sales Agents. The Sales Agents are entitled to compensation in an agreed amount not to exceed 2.0 percent of the gross price per share for any shares sold from time to time under the Sales Agreement. Concurrent with entry into the Sales Agreement, we terminated our previous sales agreement dated June 17, 2015, with BMO Capital Markets Corp., Merrill Lynch, Pierce, Fenner & Smith Incorporated and Citigroup Global Markets Inc., (the “Prior Agreement”). The Prior Agreement had an aggregate offering price of up to $250.0 million . We did not incur any penalties in connection with termination of the Prior Agreement. There were no issuances of common stock under the Sales Agreement during the three months ended March 31, 2018. Refer to Note 18, “Subsequent Events,” for additional information regarding issuances of common stock under the Sales Agreement after March 31, 2018. Issuances of common stock under the Sales Agreement during 2017 were as follows: Quarter Ended Common Stock Issued Weighted Average Sales Price Net Proceeds (in Millions) December 31, 2017 321,800 $ 93.33 $ 29.7 Issuances of common stock under the Prior Agreement during 2017 were as follows: Quarter Ended Common Stock Issued Weighted Average Sales Price Net Proceeds (in Millions) June 30, 2017 400,000 $ 85.01 $ 33.6 March 31, 2017 280,502 $ 76.47 $ 21.2 Issuance of Common Stock and Common OP Units In July 2017, we issued 298,900 shares of common stock totaling $26.4 million in connection with the acquisition of Pismo Dunes. In June 2017, we issued a total of 23,311 common OP units for total consideration of $2.0 million in connection with acquisition activity during the three months ended June 30, 2017. Conversions Subject to certain limitations, holders can convert certain series of stock and OP units to shares of our common stock at any time. Below is the activity of conversions during the three months ended March 31, 2018 and 2017 : Three Months Ended Three Months Ended Series Conversion Rate Units/Shares Converted Common Stock Units/Shares Converted Common Stock Common OP unit 1 6,777 6,777 8,579 8,579 Series A-1 preferred OP unit 2.439 3,700 9,023 5,425 13,230 Series A-4 preferred OP unit 0.4444 2,373 1,054 2,000 888 Series A-4 preferred stock 0.4444 — — 45,153 20,068 Series C preferred OP unit 1.11 — — 4,993 5,539 Dividends Dividend distributions for the three months ended March 31, 2018 were as follows: Dividend Record Date Payment Date Distribution per Share Total Distribution (thousands) Common Stock, Common OP units and Restricted Stock 3/29/2018 4/16/2018 $ 0.71 $ 56,014 Series A-4 Preferred Stock 3/16/2018 4/2/2018 $ 0.40625 $ 441 Redemptions If certain change of control transactions occur or if our common stock ceases to be listed or quoted on an exchange or quotation system, then at any time after November 26, 2019, we or the holders of shares of Series A-4 preferred stock and Series A-4 preferred OP units may cause all or any of those shares or units to be redeemed for cash at a redemption price equal to the sum of (i) the greater of (x) the amount that the redeemed shares of Series A-4 preferred stock and Series A-4 preferred OP units would have received in such transaction if they had been converted into shares of our common stock immediately prior to such transaction, or (y) $25.00 per share, plus (ii) any accrued and unpaid distributions thereon to, but not including, the redemption date. In November 2017, we redeemed all of the outstanding shares of our 7.125% Series A Cumulative Redeemable Preferred Stock. Holders received a cash payment of $25.14349 per share which included accrued and unpaid dividends. In the aggregate, we paid $85.5 million to redeem all of the 3,400,000 outstanding shares. In June 2017, we redeemed 438,448 shares of Series A-4 Cumulative Convertible Preferred Stock and 200,000 shares of Series A-4 preferred OP units from Green Courte Real Estate Partners III, LLC, GCP Fund III REIT LLC and GCP Fund III Ancillary Holding, LLC (collectively, the “Green Courte Entities”) for total consideration of $24.7 million . Accrued dividends totaling $0.2 million were also paid in connection with the redemptions. The Green Courte Entities were the sellers of the American Land Lease portfolio which we acquired in 2014 and 2015. Repurchase Program In November 2004, our Board of Directors authorized us to repurchase up to 1,000,000 shares of our common stock. We have 400,000 common shares remaining in the repurchase program. No common shares were repurchased during the three months ended March 31, 2018 or 2017 . There is no expiration date specified for the buyback program.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2018
Share-based Compensation [Abstract]
Share-Based Compensation	Share-Based Compensation As of March 31, 2018 , we have two share-based compensation plans; the Sun Communities, Inc. 2015 Equity Incentive Plan (“2015 Equity Incentive Plan”) and the First Amended and Restated 2004 Non-Employee Director Option Plan (“2004 Non-Employee Director Option Plan”). We believe granting equity awards will provide certain executives, key employees and directors additional incentives to promote our financial success, and promote employee and director retention by providing an opportunity to acquire or increase the direct proprietary interest of those individuals in our operations and future. The following table shows details on grants of equity awards during the three months ended March 31, 2018: Grant Period Type Plan Shares Granted Grant Date Fair Value Per Share Vesting Type Vesting Anniversary Percentage 2018 Key Employees 2015 Equity Incentive Plan 16,500 $ 88.30 (1) Time Based 2nd 35.0 % 3rd 35.0 % 4th 20.0 % 5th 5.0 % 6th 5.0 % 2018 Key Employees 2015 Equity Incentive Plan 44,600 $ 85.29 (1) Time Based 20.0% annually over 5 years 2018 Executive Officers 2015 Equity Incentive Plan 60,000 $ 87.24 (1) Time Based 20.0% annually over 5 years 2018 Executive Officers 2015 Equity Incentive Plan 90,000 $ 65.24 (2) Market Condition 3rd 100.0 % 2018 Directors 2004 Non-Employee Director Option Plan 16,800 $ 85.28 (1) Time Based 3rd 100.0 % (1) The fair value of the grants were determined by using the closing price of our common stock on the dates the shares were issued. (2) Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $87.24 . Based on the Monte Carlo simulation we expect 74.8% of the 90,000 shares to vest. Options During the three months ended March 31, 2017, 1,500 shares of common stock were issued in connection with the exercise of stock options with net proceeds of $0.1 million . There were no stock option exercises during the three months ended March 31, 2018. Vesting The vesting requirements for 93,647 restricted shares granted to our executives, directors and employees were satisfied during the three months ended March 31, 2018 .

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting We group our operating segments into reportable segments that provide similar products and services. Each operating segment has discrete financial information evaluated regularly by our chief operating decision maker in evaluating and assessing performance. We have two reportable segments: (i) Real Property Operations and (ii) Home Sales and Rentals. The Real Property Operations segment owns, operates, develops, or has an interest in a portfolio of MH and RV communities, and is in the business of acquiring, operating, and expanding MH and RV communities. The Home Sales and Rentals segment offers MH and RV park model sales and leasing services to tenants and prospective tenants of our communities. Transactions between our segments are eliminated in consolidation. Transient RV revenue is included in the Real Property Operations segment revenues and is expected to approximate $85.5 million annually. This transient RV revenue was recognized 25.8 percent in the first quarter, and is expected to be recognized 20.6 percent, 37.4 percent, and 16.2 percent in the second, third, and fourth quarters, respectively. Transient revenue was $78.0 million for the year ended December 31, 2017. We recognized 27.2 percent in the first quarter, 20.1 percent in the second quarter, 36.9 percent in the third quarter, and 15.8 percent in the fourth quarter. A presentation of segment financial information is summarized as follows (in thousands): Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated Revenues $ 203,779 $ 47,920 $ 251,699 $ 189,273 $ 39,602 $ 228,875 Operating expenses/Cost of sales 70,732 31,741 102,473 64,977 25,985 90,962 Net operating income/Gross profit 133,047 16,179 149,226 124,296 13,617 137,913 Adjustments to arrive at net income / (loss): Interest and other revenues, net 6,276 (59 ) 6,217 5,525 — 5,525 Home selling expenses — (3,290 ) (3,290 ) — (3,111 ) (3,111 ) General and administrative (17,187 ) (2,744 ) (19,931 ) (15,721 ) (2,211 ) (17,932 ) Transaction costs — — — (2,411 ) 25 (2,386 ) Depreciation and amortization (50,508 ) (15,929 ) (66,437 ) (47,330 ) (15,436 ) (62,766 ) Extinguishment of debt (196 ) — (196 ) (466 ) — (466 ) Interest (31,134 ) (4 ) (31,138 ) (31,319 ) (3 ) (31,322 ) Interest on mandatorily redeemable preferred OP units (619 ) — (619 ) (784 ) — (784 ) Catastrophic weather related charges, net 2,357 (144 ) 2,213 (87 ) — (87 ) Other (expense) / income, net (2,616 ) (1 ) (2,617 ) 631 208 839 Current tax expense (96 ) (78 ) (174 ) (123 ) (55 ) (178 ) Deferred tax benefit 347 — 347 300 — 300 Net income / (loss) 39,671 (6,070 ) 33,601 32,511 (6,966 ) 25,545 Less: Preferred return to preferred OP units 1,080 — 1,080 1,174 — 1,174 Less: Amounts attributable to noncontrolling interests 2,400 (306 ) 2,094 1,483 (395 ) 1,088 Net income / (loss) attributable to Sun Communities, Inc. 36,191 (5,764 ) 30,427 29,854 (6,571 ) 23,283 Less: Preferred stock distributions 441 — 441 2,179 — 2,179 Net income / (loss) attributable to Sun Communities, Inc. common stockholders $ 35,750 $ (5,764 ) $ 29,986 $ 27,675 $ (6,571 ) $ 21,104 March 31, 2018 December 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated Identifiable assets: Investment property, net $ 5,162,460 $ 480,194 $ 5,642,654 $ 5,172,521 $ 472,833 $ 5,645,354 Cash and cash equivalents (1,483 ) 16,636 15,153 (7,649 ) 17,776 10,127 Inventory of manufactured homes — 36,311 36,311 — 30,430 30,430 Notes and other receivables, net 177,247 16,604 193,851 149,798 13,698 163,496 Collateralized receivables, net 123,155 — 123,155 128,246 — 128,246 Other assets, net 133,489 5,040 138,529 130,455 3,849 134,304 Total assets $ 5,594,868 $ 554,785 $ 6,149,653 $ 5,573,371 $ 538,586 $ 6,111,957

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have elected to be taxed as a real estate investment trust (“REIT”) pursuant to Section 856(c) of the Internal Revenue Code of 1986, as amended (“Code”). In order for us to qualify as a REIT, at least 95 percent of our gross income in any year must be derived from qualifying sources. In addition, a REIT must distribute annually at least 90 percent of its REIT taxable income (calculated without any deduction for dividends paid and excluding capital gain) to its stockholders and meet other tests. Qualification as a REIT involves the satisfaction of numerous requirements (on an annual and quarterly basis) established under highly technical and complex Code provisions for which there are limited judicial or administrative interpretations, and involves the determination of various factual matters and circumstances not entirely within our control. In addition, frequent changes occur in the area of REIT taxation which requires us to continually monitor our tax status. We analyzed the various REIT tests and confirmed that we continued to qualify as a REIT for the quarter ended March 31, 2018 . As a REIT, we generally will not be subject to United States (“U.S.”) federal income taxes at the corporate level on the ordinary taxable income we distribute to our stockholders as dividends. If we fail to qualify as a REIT in any taxable year, our taxable income could be subject to U.S. federal income tax at regular corporate rates (including any applicable alternative minimum tax). Even if we qualify as a REIT, we may be subject to certain state and local income taxes as well as U.S. federal income and excise taxes on our undistributed income. In addition, taxable income from non-REIT activities managed through taxable REIT subsidiaries is subject to federal, state, and local income taxes. The Company is also subject to local income taxes in Canada as a result of the acquisition of Carefree in 2016. We do not provide for withholding taxes on our undistributed earnings from our Canadian subsidiaries as they are reinvested and will continue to be reinvested indefinitely outside of the U.S. Our taxable REIT subsidiaries are subject to U.S. federal income taxes as well as state and local income and franchise taxes. In addition, our Canadian subsidiaries are subject to income tax in Canada. Deferred tax assets and liabilities reflect the impact of temporary differences between the amounts of assets and liabilities for financial reporting purposes and the bases of such assets and liabilities as measured by tax laws. Deferred tax assets are reduced, if necessary, by a valuation allowance to the amount where realization is more likely than not assured after considering all available evidence. Our temporary differences primarily relate to net operating loss carryforwards, depreciation and basis differences between tax and U.S. GAAP on our Canadian investments. Generally, full valuation allowances are recorded against almost all U.S. federal deferred tax assets. Deferred tax liabilities of $21.6 million (Canada) and $0.1 million (U.S.) have been recorded in relation to corporate entities and included in “Other liabilities” in our Consolidated Balance Sheets as of March 31, 2018 . There were no U.S. federal deferred tax assets or liabilities included in our Consolidated Balance sheets as of December 31, 2017. We had no unrecognized tax benefits as of March 31, 2018 and 2017 . We do not expect significant changes in tax positions that would result in unrecognized tax benefits within one year of March 31, 2018 . We recorded a current tax expense for federal, state, and Canadian income taxes of approximately $0.2 million for the three months ended March 31, 2018 and 2017. We recorded $0.3 million of deferred tax benefit in our Consolidated Statements of Operations for the three months ended March 31, 2018 and March 31, 2017. In 2017, SHS underwent an audit by the Internal Revenue Service for the 2015 tax year. Upon conclusion of the audit, no adjustment was required.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share We have outstanding stock options, unvested restricted common shares, and Series A-4 Preferred Stock, and our Operating Partnership has: outstanding common OP units; Series A-1 preferred OP units; Series A-3 preferred OP units; Series A-4 preferred OP units; Series C preferred OP units; and Aspen preferred OP Units, which, if converted or exercised, may impact dilution. Computations of basic and diluted earnings / (loss) per share were as follows (in thousands, except per share data): Three Months Ended March 31, Numerator 2018 2017 Net income attributable to common stockholders $ 29,986 $ 21,104 Allocation to restricted stock awards (303 ) (253 ) Basic earnings: Net income attributable to common stockholders after allocation 29,683 20,851 Allocation to restricted stock awards 303 253 Diluted earnings: Net income attributable to common stockholders after allocation $ 29,986 $ 21,104 Denominator Weighted average common shares outstanding 78,855 72,677 Add: dilutive stock options 2 2 Add: dilutive restricted stock 607 441 Diluted weighted average common shares and securities 79,464 73,120 Earnings per share available to common stockholders after allocation: Basic $ 0.38 $ 0.29 Diluted $ 0.38 $ 0.29 We have excluded certain securities from the computation of diluted earnings per share because the inclusion of these securities would have been anti-dilutive for the periods presented. The following table presents the outstanding securities that were excluded from the computation of diluted earnings per share as of March 31, 2018 and 2017 (in thousands): As of March 31, 2018 2017 Common OP units 2,739 2,750 Series A-1 preferred OP units 342 362 Series A-3 preferred OP units 40 40 Series A-4 preferred OP units 422 632 Series A-4 preferred stock 1,085 1,637 Series C preferred OP units 316 328 Aspen preferred OP units 1,284 1,284 Total securities 6,228 7,033

Derivative Instruments And Hedg

Derivative Instruments And Hedging Activities	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments And Hedging Activities	Derivative Instruments and Hedging Activities Our objective in using interest rate derivatives is to manage exposure to interest rate movements thereby minimizing the effect of interest rate changes and the effect it could have on future cash flows. Interest rate caps are used to accomplish this objective. We do not enter into derivative instruments for speculative purposes nor do we have any swaps in a hedging arrangement. The following table provides the terms of our interest rate derivative contracts that were in effect as of March 31, 2018 : Type Purpose Effective Date Maturity Date Notional (in millions) Based on Variable Rate Cap Rate Spread Effective Fixed Rate Cap Cap Floating Rate 4/1/2015 4/1/2018 $ 150.1 3 Month LIBOR 3.5640% 9.0000% —% N/A Cap Cap Floating Rate 10/3/2016 5/1/2023 $ 9.6 3 Month LIBOR 4.3640% 11.0200% —% N/A During the three months ended March 31, 2018, we entered into an interest rate derivative contract, effective April 1, 2018, that replaced the contracted that expired on April 1, 2018 in the table above. The new contract is a floating rate cap that matures on April 1, 2021 , with a notional amount $142.9 million and cap rate of 20.93 percent . In accordance with ASC Topic 815, “ Derivatives and Hedging, ” derivative instruments are recorded at fair value in Other assets, net or Other liabilities on the Consolidated Balance Sheets. As of March 31, 2018 and December 31, 2017 , the fair value of our derivatives was zero .

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Of Financial Instruments	Fair Value of Financial Instruments Our financial instruments consist primarily of cash and cash equivalents, accounts and notes receivable, accounts payable, derivative instruments, and debt. ASC Topic 820 “ Fair Value Measurements and Disclosures, ” requires disclosure regarding determination of fair value for assets and liabilities and establishes a hierarchy under which these assets and liabilities must be grouped, based on significant levels of observable or unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumption. This hierarchy requires the use of observable market data when available. These two types of inputs have created the following fair value hierarchy: Level 1 —Quoted unadjusted prices for identical instruments in active markets; Level 2 —Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and Level 3 —Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. We utilize fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. The following methods and assumptions were used in order to estimate the fair value of each class of financial instruments for which it is practicable to estimate that value: Derivative Instruments The derivative instruments held by us are interest rate cap agreements for which quoted market prices are indirectly available. For those derivatives, we use model-derived valuations in which all significant inputs and significant value drivers are observable in active markets provided by brokers or dealers to determine the fair value of derivative instruments on a recurring basis (Level 2). Refer to Note 14 , “Derivative Instruments and Hedging Activities.” Installment Notes Receivable on Manufactured Homes The net carrying value of the installment notes receivable on manufactured homes estimates the fair value as the interest rates in the portfolio are comparable to current prevailing market rates (Level 2). Refer to Note 5 , “Notes and Other Receivables.” Long-Term Debt and Lines of Credit The fair value of long-term debt (excluding the secured borrowing) is based on the estimates of management and on rates currently quoted, rates currently prevailing for comparable loans, and instruments of comparable maturities (Level 2). Refer to Note 8 , “Debt and Lines of Credit.” Collateralized Receivables and Secured Borrowings The fair value of these financial instruments offset each other as our collateralized receivables represent a transfer of financial assets and the cash proceeds received from these transactions have been classified as a secured borrowing on the Consolidated Balance Sheets. The net carrying value of the collateralized receivables estimates the fair value as the interest rates in the portfolio are comparable to current prevailing market rates (Level 2). Refer to Note 4 , “Collateralized Receivables and Transfers of Financial Assets.” Financial Liabilities We estimate the fair value of our contingent consideration liability based on discounting of future cash flows using market interest rates and adjusting for non-performance risk over the remaining term of the liability (Level 2). Other Financial Instruments The carrying values of cash and cash equivalents, accounts receivable, and accounts payable approximate their fair market values due to the short-term nature of these instruments. The table below sets forth our financial assets and liabilities that required disclosure of fair value on a recurring basis as of March 31, 2018 . The table presents the carrying values and fair values of our financial instruments as of March 31, 2018 and December 31, 2017 , that were measured using the valuation techniques described above (in thousands). The table excludes other financial instruments such as cash and cash equivalents, accounts receivable, and accounts payable as the carrying values associated with these instruments approximate fair value since their maturities are less than one year. March 31, 2018 December 31, 2017 Financial assets Carrying Value Fair Value Carrying Value Fair Value Installment notes receivable on manufactured homes, net $ 124,738 $ 124,738 $ 115,797 $ 115,797 Collateralized receivables, net 123,155 123,155 128,246 128,246 Financial liabilities Debt (excluding secured borrowings) $ 2,863,563 $ 2,641,997 $ 2,908,799 $ 2,726,770 Secured borrowings 124,077 124,077 129,182 129,182 Lines of credit 141,800 141,800 41,257 41,257 Other liabilities (contingent consideration) 7,069 7,069 6,976 6,976

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recent Accounting Pronouncements - Adopted On January 1, 2018, we adopted ASU 2014-09 “ Revenue from Contracts with Customers (Topic 606). ” Refer to Note 2, “Revenue” for information regarding our adoption of this guidance. On January 1, 2018 we adopted ASU 2017-09 “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting.” This update provided clarity and reduced both diversity in practice and cost and complexity when applying the guidance in Topic 718, Compensation - Stock Compensation, regarding a change to the terms or conditions of a share-based payment award. There was no initial impact that resulted from adoption of this guidance; it will be applied should a modification occur. On January 1, 2018, we adopted ASU 2017-01 “Business Combinations (Topic 805): Clarifying the Definition of a Business.” This update clarified the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill, and consolidation. Under previous guidance, substantially all of our property acquisitions were accounted for as business combinations with identifiable assets and liabilities measured at fair value, and acquisition related costs expensed as incurred and reported as Transaction costs in our Consolidations Statements of Operations. With the adoption of ASU 2017-01, we expect that substantially all of our future property acquisitions will be accounted for as asset acquisitions. We will allocate the purchase price of these properties on a relative fair value basis and capitalize direct acquisition related costs as part of the purchase price. Acquisitions costs that do not meet the criteria to be capitalized will be expensed as incurred and presented as General and administrative costs in our Consolidated Statements of Operations. On January 1, 2018, we adopted ASU 2016-18 “Statement of Cash Flows (Topic 230): Restricted Cash.” This update required inclusion of restricted cash and restricted cash equivalents with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Our restricted cash consists of amounts primarily held in deposit for tax, insurance and repair escrows held by lenders in accordance with certain debt agreements. Restricted cash is included as a component of Other assets, net on the Consolidated Balance Sheets. Changes in restricted cash are reported in our Consolidated Statements of Cash Flows as operating, investing or financing activities based on the nature of the underlying activity. The following table reconciles our beginning-of-period and end-of-period balances of cash, cash equivalents and restricted cash for the periods shown (in thousands): March 31, 2018 December 31, 2017 March 31, 2017 December 31, 2016 Cash and cash equivalents $ 15,153 $ 10,127 $ 10,919 $ 8,164 Restricted cash 12,271 13,382 15,791 17,149 Cash, cash equivalents and restricted cash $ 27,424 $ 23,509 $ 26,710 $ 25,313 Recent Accounting Pronouncements - Not Yet Adopted In June 2016, the FASB issued ASU 2016-13 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” This update replaces the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. We are in the initial phases of evaluating how this guidance will impact our accounting policies regarding assessment of, and allowance for, loan losses. In February 2016, the FASB issued ASU 2016-02 “ Leases (Topic 842). ” The core principle of this update is that a lessee should recognize the assets and liabilities that arise from leases while the accounting by a lessor is largely unchanged from that applied under previous GAAP. The amendments in this update are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Our income from real property and rental home revenue streams is derived from rental agreements where we are the lessor. As noted above, the lessor accounting model is largely unchanged by this update. We are the lessee in other arrangements, primarily for our executive offices, ground leases at five communities, and certain equipment. We are currently evaluating our inventory of such leases to determine which will require recognition of right of use assets and corresponding lease liabilities, and the related disclosure requirements thereto. We intend to adopt the practical expedients associated with this guidance.

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies Legal Proceedings We are involved in various legal proceedings arising in the ordinary course of business. All such proceedings, taken together, are not expected to have a material adverse impact on our results of operations or financial condition. Catastrophic Weather Related Estimates In September 2017, our communities in Florida and Georgia sustained damages from Hurricane Irma. The table below sets forth estimated losses (in millions). Future changes to estimated losses will be recognized in the period(s) in which they are determined. Damages (1) Impaired Assets - Florida Keys Total Total estimated losses - December 31, 2017 $ 21.3 $ 10.4 $ 31.7 Change in estimated losses 3.8 — 3.8 Total estimated losses - March 31, 2018 $ 25.1 $ 10.4 $ 35.5 (1) Damages losses are comprised primarily by tree and debris removal, common area repairs and minor flooding. We maintain property, casualty, flood and business interruption insurance for our community portfolio, subject to customary deductibles and limits. The table below sets forth estimated insurance recoveries (in millions). Actual insurance recoveries could vary significantly from our estimates. Future changes to estimated insurance recoveries will be recognized in the period(s) in which they are determined. Three Months Ended March 31, 2018 Damages (1) Loss of Earnings Redevelopment Costs in Excess of Impairment Charges Total Total estimated insurance receivable - December 31, 2017 $ 23.7 $ — $ — $ 23.7 Change in estimated insurance recoveries 6.0 — — 6.0 Advances from insurer (5.0 ) — — (5.0 ) Total estimated insurance receivable - March 31, 2018 $ 24.7 $ — $ — $ 24.7 Changes in estimated insurance recoveries for damages during the three months ended March 31, 2018, were primarily the result of incremental losses where deductibles were previously met. Additionally, previous recovery estimates were refined as damage losses were attributed to specific asset deductible categories. The change in estimated losses and changes in estimated insurance recoveries during the three months ended March 31, 2018, resulted in a net favorable adjustment of $2.2 million to Catastrophic weather related charges, net in our Consolidated Statements of Operations. We are actively working with our insurer on claims for lost earnings and redevelopment costs greater than the asset impairment charge for the three Florida Keys communities. The three impaired Florida Keys communities will require redevelopment followed by a tenant lease-up period. As such, we currently cannot estimate a date when operating results will be restored to pre-hurricane levels. Our business interruption insurance policy provides for up to 60 months of coverage from the date of restoration.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events In April 2018, we issued 220,000 shares of common stock through our At-the-Market equity sales program at a weighted average price of $91.31 per share. Net proceeds from the sales were $19.8 million . We have evaluated our Consolidated Financial Statements for subsequent events through the date that this Form 10-Q was issued.

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table disaggregates our revenue by major source (in thousands): Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated REVENUE Income from real property $ 197,211 $ — $ 197,211 $ 183,054 $ — $ 183,054 Revenue from home sales — 34,900 34,900 — 27,263 27,263 Rental home revenue — 13,020 13,020 — 12,339 12,339 Ancillary revenues 6,568 — 6,568 6,219 — 6,219 Interest 5,316 — 5,316 4,646 — 4,646 Brokerage commissions and other revenues, net 960 (59 ) 901 879 — 879 Total revenue $ 210,055 $ 47,861 $ 257,916 $ 194,798 $ 39,602 $ 234,400

Real Estate Acquisitions (Table

Real Estate Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The following table summarizes the amounts of assets acquired net of liabilities assumed at the acquisition date and the consideration paid for the acquisitions completed in 2017 (in thousands): At Acquisition Date Colony in the Wood Emerald Coast Lazy J Ranch Ocean West Caliente Sands Pismo Dunes Arbor Woods Sunset Lakes 49er Village Total Investment in property $ 31,818 $ 19,400 $ 13,938 $ 9,453 $ 8,640 $ 21,260 $ 15,725 $ 7,835 $ 12,890 $ 140,959 Notes receivable — — — — — — 23 — — 23 Inventory of manufactured homes — — 2 — 21 — 465 — — 488 In-place leases and other tangible assets 660 100 360 220 210 660 730 210 110 3,260 Total identifiable assets acquired net of liabilities assumed $ 32,478 $ 19,500 $ 14,300 $ 9,673 $ 8,871 $ 21,920 $ 16,943 $ 8,045 $ 13,000 $ 144,730 Consideration Cash $ 32,478 $ 19,500 $ 14,300 $ 5,081 $ 8,871 $ — $ 14,943 $ 8,045 $ 13,000 116,218 Equity — — — — — 26,410 2,000 — — 28,410 Liabilities assumed — — — 4,592 — 510 — — — 5,102 Cash proceeds from seller — — — — — (5,000 ) — — — (5,000 ) Total consideration $ 32,478 $ 19,500 $ 14,300 $ 9,673 $ 8,871 $ 21,920 $ 16,943 $ 8,045 $ 13,000 $ 144,730

Collateralized Receivables an29

Collateralized Receivables and Transfers of Financial Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase price percentage	Number of Payments Repurchase Percentage Fewer than or equal to 15 100 % Greater than 15 but fewer than 64 90 % Equal to or greater than 64 but fewer than 120 65 % 120 or more 50 %
Schedule of collateralized loans	Three Months Ended March 31, 2018 Beginning balance $ 129,182 Principal payments and payoffs from our customers (2,557 ) Principal reduction from repurchased homes (2,548 ) Total activity (5,105 ) Ending balance $ 124,077
Collateralized Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for collateralized and installment notes receivable	The following table sets forth the allowance for the collateralized receivables as of March 31, 2018 (in thousands): Three Months Ended March 31, 2018 Beginning balance $ (936 ) Lower of cost or market write-downs 313 Increase to reserve balance (299 ) Total activity 14 Ending balance $ (922 )

Notes And Other Receivables (Ta

Notes And Other Receivables (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Schedule of notes and other receivables	The following table sets forth certain information regarding notes and other receivables (in thousands): March 31, 2018 December 31, 2017 Installment notes receivable on manufactured homes, net $ 124,738 $ 115,797 Other receivables, net 69,113 47,699 Total notes and other receivables, net $ 193,851 $ 163,496
Schedule of Installment Notes Receivable	The change in the aggregate gross principal balance of the installment notes receivable is as follows (in thousands): Three Months Ended March 31, 2018 Beginning balance $ 116,174 Financed sales of manufactured homes 12,842 Principal payments and payoffs from our customers (1,912 ) Principal reduction from repossessed homes (1,935 ) Total activity 8,995 Ending balance $ 125,169
Installment Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for collateralized and installment notes receivable	The following table sets forth the allowance change for the installment notes receivable as follows (in thousands): Three Months Ended March 31, 2018 Beginning balance $ (377 ) Lower of cost or market write-downs 175 Increase to reserve balance (229 ) Total activity (54 ) Ending balance $ (431 )

Intangible Assets Intangible As

Intangible Assets Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Finite-Lived Intangible Assets, Net [Abstract]
Schedule of Finite-Lived Intangible Assets	The gross carrying amounts, and accumulated amortization are as follows (in thousands): March 31, 2018 December 31, 2017 Intangible Asset Useful Life Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Ground leases 8-57 years $ 32,165 $ (1,632 ) $ 32,165 $ (1,409 ) In-place leases 7 years 101,365 (49,066 ) 100,843 (45,576 ) Franchise fees and other intangible assets 15 years 1,880 (1,470 ) 1,880 (1,451 ) Total $ 135,410 $ (52,168 ) $ 134,888 $ (48,436 )
Schedule of Intangible Assets Amortization Expense	Total amortization expenses related to the intangible assets are as follows (in thousands): Three Months Ended Intangible Asset 2018 2017 2016 Ground leases $ 223 $ 257 $ — In-place leases 3,490 3,416 2,153 Franchise fees and other intangible assets 19 129 129 Total $ 3,732 $ 3,802 $ 2,282
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	We anticipate amortization expense for our intangible assets to be as follows for the next five years (in thousands): Year Remainder of 2018 2019 2020 2021 2022 Estimated expense $ 10,786 $ 13,685 $ 11,957 $ 11,565 $ 6,964

Consolidated Variable Interes32

Consolidated Variable Interest Entities (Tables)	3 Months Ended
	Mar. 31, 2018
DisclosureofVariableInterestEntities [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the assets and liabilities included in our Consolidated Balance Sheets after eliminations (in thousands): March 31, 2018 December 31, 2017 ASSETS Investment property, net $ 49,943 $ 50,193 Other assets 1,453 1,659 Total Assets $ 51,396 $ 51,852 LIABILITIES AND STOCKHOLDERS’ EQUITY Debt $ 41,756 $ 41,970 Other liabilities 1,326 1,468 Noncontrolling interests 4,751 4,285 Total Liabilities and Stockholders’ Equity $ 47,833 $ 47,723

Debt And Lines Of Credit (Table

Debt And Lines Of Credit (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of debt and lines of credit [Table Text Block]	The following table sets forth certain information regarding debt including premiums, discounts and deferred financing costs (in thousands): Carrying Amount Weighted Average Years to Maturity Weighted Average Interest Rates March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 Collateralized term loans - Life Companies $ 1,038,459 $ 1,044,246 13.7 13.9 3.9 % 3.9 % Collateralized term loans - FNMA 994,605 1,026,014 5.5 5.6 4.4 % 4.4 % Collateralized term loans - CMBS 408,251 410,747 4.8 5.0 5.1 % 5.1 % Collateralized term loans - FMCC 384,910 386,349 6.6 6.9 3.9 % 3.9 % Secured borrowings 124,077 129,182 15.1 15.3 10.0 % 10.0 % Lines of credit 141,800 41,257 3.0 3.1 3.0 % 2.8 % Preferred OP units - mandatorily redeemable 37,338 41,443 5.4 5.0 6.6 % 6.7 % Total debt $ 3,129,440 $ 3,079,238 8.5 8.9 4.5 % 4.5 %

Equity and Mezzanine Securiti34

Equity and Mezzanine Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Schedule of Sale of Common Stock	Issuances of common stock under the Sales Agreement during 2017 were as follows: Quarter Ended Common Stock Issued Weighted Average Sales Price Net Proceeds (in Millions) December 31, 2017 321,800 $ 93.33 $ 29.7 Issuances of common stock under the Prior Agreement during 2017 were as follows: Quarter Ended Common Stock Issued Weighted Average Sales Price Net Proceeds (in Millions) June 30, 2017 400,000 $ 85.01 $ 33.6 March 31, 2017 280,502 $ 76.47 $ 21.2
Activity of Conversions	Three Months Ended Three Months Ended Series Conversion Rate Units/Shares Converted Common Stock Units/Shares Converted Common Stock Common OP unit 1 6,777 6,777 8,579 8,579 Series A-1 preferred OP unit 2.439 3,700 9,023 5,425 13,230 Series A-4 preferred OP unit 0.4444 2,373 1,054 2,000 888 Series A-4 preferred stock 0.4444 — — 45,153 20,068 Series C preferred OP unit 1.11 — — 4,993 5,539
Schedule of Dividends Payable	Dividend Record Date Payment Date Distribution per Share Total Distribution (thousands) Common Stock, Common OP units and Restricted Stock 3/29/2018 4/16/2018 $ 0.71 $ 56,014 Series A-4 Preferred Stock 3/16/2018 4/2/2018 $ 0.40625 $ 441

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Share-based Compensation [Abstract]
Schedule of Restricted Stock Granted	The following table shows details on grants of equity awards during the three months ended March 31, 2018: Grant Period Type Plan Shares Granted Grant Date Fair Value Per Share Vesting Type Vesting Anniversary Percentage 2018 Key Employees 2015 Equity Incentive Plan 16,500 $ 88.30 (1) Time Based 2nd 35.0 % 3rd 35.0 % 4th 20.0 % 5th 5.0 % 6th 5.0 % 2018 Key Employees 2015 Equity Incentive Plan 44,600 $ 85.29 (1) Time Based 20.0% annually over 5 years 2018 Executive Officers 2015 Equity Incentive Plan 60,000 $ 87.24 (1) Time Based 20.0% annually over 5 years 2018 Executive Officers 2015 Equity Incentive Plan 90,000 $ 65.24 (2) Market Condition 3rd 100.0 % 2018 Directors 2004 Non-Employee Director Option Plan 16,800 $ 85.28 (1) Time Based 3rd 100.0 % (1) The fair value of the grants were determined by using the closing price of our common stock on the dates the shares were issued. (2) Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $87.24 . Based on the Monte Carlo simulation we expect 74.8% of the 90,000 shares to vest.

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	A presentation of segment financial information is summarized as follows (in thousands): Three Months Ended March 31, 2018 Three Months Ended March 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated Revenues $ 203,779 $ 47,920 $ 251,699 $ 189,273 $ 39,602 $ 228,875 Operating expenses/Cost of sales 70,732 31,741 102,473 64,977 25,985 90,962 Net operating income/Gross profit 133,047 16,179 149,226 124,296 13,617 137,913 Adjustments to arrive at net income / (loss): Interest and other revenues, net 6,276 (59 ) 6,217 5,525 — 5,525 Home selling expenses — (3,290 ) (3,290 ) — (3,111 ) (3,111 ) General and administrative (17,187 ) (2,744 ) (19,931 ) (15,721 ) (2,211 ) (17,932 ) Transaction costs — — — (2,411 ) 25 (2,386 ) Depreciation and amortization (50,508 ) (15,929 ) (66,437 ) (47,330 ) (15,436 ) (62,766 ) Extinguishment of debt (196 ) — (196 ) (466 ) — (466 ) Interest (31,134 ) (4 ) (31,138 ) (31,319 ) (3 ) (31,322 ) Interest on mandatorily redeemable preferred OP units (619 ) — (619 ) (784 ) — (784 ) Catastrophic weather related charges, net 2,357 (144 ) 2,213 (87 ) — (87 ) Other (expense) / income, net (2,616 ) (1 ) (2,617 ) 631 208 839 Current tax expense (96 ) (78 ) (174 ) (123 ) (55 ) (178 ) Deferred tax benefit 347 — 347 300 — 300 Net income / (loss) 39,671 (6,070 ) 33,601 32,511 (6,966 ) 25,545 Less: Preferred return to preferred OP units 1,080 — 1,080 1,174 — 1,174 Less: Amounts attributable to noncontrolling interests 2,400 (306 ) 2,094 1,483 (395 ) 1,088 Net income / (loss) attributable to Sun Communities, Inc. 36,191 (5,764 ) 30,427 29,854 (6,571 ) 23,283 Less: Preferred stock distributions 441 — 441 2,179 — 2,179 Net income / (loss) attributable to Sun Communities, Inc. common stockholders $ 35,750 $ (5,764 ) $ 29,986 $ 27,675 $ (6,571 ) $ 21,104
Reconciliation of Assets from Segment to Consolidated	March 31, 2018 December 31, 2017 Real Property Operations Home Sales and Rentals Consolidated Real Property Operations Home Sales and Rentals Consolidated Identifiable assets: Investment property, net $ 5,162,460 $ 480,194 $ 5,642,654 $ 5,172,521 $ 472,833 $ 5,645,354 Cash and cash equivalents (1,483 ) 16,636 15,153 (7,649 ) 17,776 10,127 Inventory of manufactured homes — 36,311 36,311 — 30,430 30,430 Notes and other receivables, net 177,247 16,604 193,851 149,798 13,698 163,496 Collateralized receivables, net 123,155 — 123,155 128,246 — 128,246 Other assets, net 133,489 5,040 138,529 130,455 3,849 134,304 Total assets $ 5,594,868 $ 554,785 $ 6,149,653 $ 5,573,371 $ 538,586 $ 6,111,957

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share [Table Text Block]	Computations of basic and diluted earnings / (loss) per share were as follows (in thousands, except per share data): Three Months Ended March 31, Numerator 2018 2017 Net income attributable to common stockholders $ 29,986 $ 21,104 Allocation to restricted stock awards (303 ) (253 ) Basic earnings: Net income attributable to common stockholders after allocation 29,683 20,851 Allocation to restricted stock awards 303 253 Diluted earnings: Net income attributable to common stockholders after allocation $ 29,986 $ 21,104 Denominator Weighted average common shares outstanding 78,855 72,677 Add: dilutive stock options 2 2 Add: dilutive restricted stock 607 441 Diluted weighted average common shares and securities 79,464 73,120 Earnings per share available to common stockholders after allocation: Basic $ 0.38 $ 0.29 Diluted $ 0.38 $ 0.29
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following table presents the outstanding securities that were excluded from the computation of diluted earnings per share as of March 31, 2018 and 2017 (in thousands): As of March 31, 2018 2017 Common OP units 2,739 2,750 Series A-1 preferred OP units 342 362 Series A-3 preferred OP units 40 40 Series A-4 preferred OP units 422 632 Series A-4 preferred stock 1,085 1,637 Series C preferred OP units 316 328 Aspen preferred OP units 1,284 1,284 Total securities 6,228 7,033

Derivative Instruments And He38

Derivative Instruments And Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following table provides the terms of our interest rate derivative contracts that were in effect as of March 31, 2018 : Type Purpose Effective Date Maturity Date Notional (in millions) Based on Variable Rate Cap Rate Spread Effective Fixed Rate Cap Cap Floating Rate 4/1/2015 4/1/2018 $ 150.1 3 Month LIBOR 3.5640% 9.0000% —% N/A Cap Cap Floating Rate 10/3/2016 5/1/2023 $ 9.6 3 Month LIBOR 4.3640% 11.0200% —% N/A

Fair Value of Financial Instr39

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The table below sets forth our financial assets and liabilities that required disclosure of fair value on a recurring basis as of March 31, 2018 . The table presents the carrying values and fair values of our financial instruments as of March 31, 2018 and December 31, 2017 , that were measured using the valuation techniques described above (in thousands). The table excludes other financial instruments such as cash and cash equivalents, accounts receivable, and accounts payable as the carrying values associated with these instruments approximate fair value since their maturities are less than one year. March 31, 2018 December 31, 2017 Financial assets Carrying Value Fair Value Carrying Value Fair Value Installment notes receivable on manufactured homes, net $ 124,738 $ 124,738 $ 115,797 $ 115,797 Collateralized receivables, net 123,155 123,155 128,246 128,246 Financial liabilities Debt (excluding secured borrowings) $ 2,863,563 $ 2,641,997 $ 2,908,799 $ 2,726,770 Secured borrowings 124,077 124,077 129,182 129,182 Lines of credit 141,800 141,800 41,257 41,257 Other liabilities (contingent consideration) 7,069 7,069 6,976 6,976

Recent Accounting Pronounceme40

Recent Accounting Pronouncements (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Changes and Error Corrections [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table reconciles our beginning-of-period and end-of-period balances of cash, cash equivalents and restricted cash for the periods shown (in thousands): March 31, 2018 December 31, 2017 March 31, 2017 December 31, 2016 Cash and cash equivalents $ 15,153 $ 10,127 $ 10,919 $ 8,164 Restricted cash 12,271 13,382 15,791 17,149 Cash, cash equivalents and restricted cash $ 27,424 $ 23,509 $ 26,710 $ 25,313
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table reconciles our beginning-of-period and end-of-period balances of cash, cash equivalents and restricted cash for the periods shown (in thousands): March 31, 2018 December 31, 2017 March 31, 2017 December 31, 2016 Cash and cash equivalents $ 15,153 $ 10,127 $ 10,919 $ 8,164 Restricted cash 12,271 13,382 15,791 17,149 Cash, cash equivalents and restricted cash $ 27,424 $ 23,509 $ 26,710 $ 25,313

Commitments And Contingencies (

Commitments And Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Loss Contingencies by Contingency	The table below sets forth estimated losses (in millions). Future changes to estimated losses will be recognized in the period(s) in which they are determined. Damages (1) Impaired Assets - Florida Keys Total Total estimated losses - December 31, 2017 $ 21.3 $ 10.4 $ 31.7 Change in estimated losses 3.8 — 3.8 Total estimated losses - March 31, 2018 $ 25.1 $ 10.4 $ 35.5 (1) Damages losses are comprised primarily by tree and debris removal, common area repairs and minor flooding.
Business Insurance Recoveries	Three Months Ended March 31, 2018 Damages (1) Loss of Earnings Redevelopment Costs in Excess of Impairment Charges Total Total estimated insurance receivable - December 31, 2017 $ 23.7 $ — $ — $ 23.7 Change in estimated insurance recoveries 6.0 — — 6.0 Advances from insurer (5.0 ) — — (5.0 ) Total estimated insurance receivable - March 31, 2018 $ 24.7 $ — $ — $ 24.7

Revenue (Details)

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 257,916	$ 234,400
Income From Real Property [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	197,211	183,054
Revenue From Home Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,900	27,263
Rental Home Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	13,020	12,339
Ancillary Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	6,568	6,219
Interest [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	5,316	4,646
Brokerage Commissions And Other Revenues, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	901	879
Real Property Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	210,055	194,798
Real Property Operations Segment [Member] | Income From Real Property [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	197,211	183,054
Real Property Operations Segment [Member] | Revenue From Home Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Real Property Operations Segment [Member] | Rental Home Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Real Property Operations Segment [Member] | Ancillary Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	6,568	6,219
Real Property Operations Segment [Member] | Interest [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	5,316	4,646
Real Property Operations Segment [Member] | Brokerage Commissions And Other Revenues, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	960	879
Home Sales and Home Rentals Segment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	47,861	39,602
Home Sales and Home Rentals Segment [Member] | Income From Real Property [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Home Sales and Home Rentals Segment [Member] | Revenue From Home Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	34,900	27,263
Home Sales and Home Rentals Segment [Member] | Rental Home Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	13,020	12,339
Home Sales and Home Rentals Segment [Member] | Ancillary Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Home Sales and Home Rentals Segment [Member] | Interest [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	0	0
Home Sales and Home Rentals Segment [Member] | Brokerage Commissions And Other Revenues, Net [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ (59)	$ 0

Revenue Contract Balances (Deta

Revenue Contract Balances (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset, Reclassified to Receivable	$ 28.6	$ 13.8

Real Estate Acquisitions Real E

Real Estate Acquisitions Real Estate Acquisitions, Narrative (Details)	1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)	Mar. 31, 2018USD ($)propertiessites	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)sites	Nov. 30, 2017sites	Jul. 31, 2017sites	May 31, 2017sites	Apr. 20, 2017sites
Business Acquisition [Line Items]
Number of Units in Real Estate Property | properties		0
Transaction costs		$ 0	$ 2,386,000
Total consideration transferred		2,000,000		$ 144,730,000
Real Estate, Dispositions and Other		$ 0
Colony In The Wood [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites				383
Total consideration transferred				$ 32,478,000
Emerald Coast [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites					201
Total consideration transferred				19,500,000
Lazy J Ranch [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites		220
Total consideration transferred				14,300,000
Ocean West [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites		130
Total consideration transferred				9,673,000
Caliente Sands [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites		118
Total consideration transferred				8,871,000
Arbor Woods [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites		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	$ 26,400,000			$ 21,920,000
Subsequent Land Acquisition [Member]
Business Acquisition [Line Items]
Number of Units in Real Estate Property | sites								841
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

Real Estate Acquisitions, Sched

Real Estate Acquisitions, Schedule of Other Acquisitions Purchase Price Allocation (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
At acquistion date
Investment in property			$ 140,959
Notes receivable			23
Inventory of manufactured homes			488
In-place leases and other tangible assets			3,260
Total identifiable assets acquired and liabilities assumed			144,730
Consideration
Cash			116,218
Equity			28,410
Liabilities assumed			5,102
Cash proceeds from seller			(5,000)
Total consideration transferred		$ 2,000	144,730
Colony In The Wood [Member]
At acquistion date
Investment in property			31,818
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			660
Total identifiable assets acquired and liabilities assumed			32,478
Consideration
Cash			32,478
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			32,478
Emerald Coast [Member]
At acquistion date
Investment in property			19,400
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			100
Total identifiable assets acquired and liabilities assumed			19,500
Consideration
Cash			19,500
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			19,500
Lazy J Ranch [Member]
At acquistion date
Investment in property			13,938
Notes receivable			0
Inventory of manufactured homes			2
In-place leases and other tangible assets			360
Total identifiable assets acquired and liabilities assumed			14,300
Consideration
Cash			14,300
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			14,300
Ocean West [Member]
At acquistion date
Investment in property			9,453
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			220
Total identifiable assets acquired and liabilities assumed			9,673
Consideration
Cash			5,081
Equity			0
Liabilities assumed			4,592
Cash proceeds from seller			0
Total consideration transferred			9,673
Caliente Sands [Member]
At acquistion date
Investment in property			8,640
Notes receivable			0
Inventory of manufactured homes			21
In-place leases and other tangible assets			210
Total identifiable assets acquired and liabilities assumed			8,871
Consideration
Cash			8,871
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			8,871
Pismo Dunes [Member]
At acquistion date
Investment in property			21,260
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			660
Total identifiable assets acquired and liabilities assumed			21,920
Consideration
Cash			0
Equity			26,410
Liabilities assumed			510
Cash proceeds from seller			(5,000)
Total consideration transferred	$ 26,400		21,920
Arbor Woods [Member]
At acquistion date
Investment in property			15,725
Notes receivable			23
Inventory of manufactured homes			465
In-place leases and other tangible assets			730
Total identifiable assets acquired and liabilities assumed			16,943
Consideration
Cash			14,943
Equity			2,000
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			16,943
Sunset Lakes [Member]
At acquistion date
Investment in property			7,835
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			210
Total identifiable assets acquired and liabilities assumed			8,045
Consideration
Cash			8,045
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			8,045
Far Horizons 49er Village [Member]
At acquistion date
Investment in property			12,890
Notes receivable			0
Inventory of manufactured homes			0
In-place leases and other tangible assets			110
Total identifiable assets acquired and liabilities assumed			13,000
Consideration
Cash			13,000
Equity			0
Liabilities assumed			0
Cash proceeds from seller			0
Total consideration transferred			$ 13,000

Real Estate Acquisitions Real46

Real Estate Acquisitions Real Estate Acquisitions, Schedule of Disposed Properties (Details)	3 Months Ended
	Mar. 31, 2018USD ($)properties
Business Combinations [Abstract]
Real Estate, Dispositions and Other | $	$ 0
Number of Units in Real Estate Property | properties	0

Collateralized Receivables an47

Collateralized Receivables and Transfers of Financial Assets, Repurchase price percentage (Details) - Collateralized Receivables [Member]	3 Months Ended
	Mar. 31, 2018
Less than or equal to 15 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percentage	100.00%
Greater than 15 but less than 64 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percentage	90.00%
Equal to or greater than 64 but less than 120 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percentage	65.00%
120 or more [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase Percentage	50.00%

Collateralized Receivables an48

Collateralized Receivables and Transfers of Financial Assets, Schedule of collateralized loans (Details) - Collateralized Receivables [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 129,182
Principal payments and payoffs from our customers	(2,557)
Principal reduction from repurchased homes	2,548
Total activity	(5,105)
Ending balance	$ 124,077

Collateralized Receivables an49

Collateralized Receivables and Transfers of Financial Assets Collateralized Receivables and Transfers of Financial Assets, Allowance for Collateralized Receivables (Details) - Collateralized Receivables [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 936
Lower of cost or market write-downs	313
Increase to reserve balance	299
Total activity	14
Ending balance	$ (922)

Collateralized Receivables an50

Collateralized Receivables and Transfers of Financial Assets, Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes and other receivables, net	$ 193,851		$ 163,496
Interest income and expense, net	2,800	$ 3,300
Collateralized Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Allowance	$ (922)		$ 936
Receivable With Imputed Interest, Term	15 years 1 month 6 days		15 years 3 months 18 days
Financing Receivable, Gross	$ 124,077		$ 129,182
Receivable with Imputed Interest, Effective Yield (Interest Rate)	10.00%		10.00%
Carrying Value [Member] | Collateralized Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes and other receivables, net	$ 123,200		$ 128,246

Notes and Other Receivables, Sc

Notes and Other Receivables, Schedule of notes and other receivables (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total notes and other receivables, net	$ 193,851	$ 163,496
Other receivables, net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total notes and other receivables, net	$ 69,113	47,699
Carrying Value [Member] | Installment notes receivable on manufactured homes, net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total notes and other receivables, net		$ 115,797

Notes And Other Receivables Not

Notes And Other Receivables Notes and Other Receivables, Installment notes receivable on manufactured homes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	$ 193,851	$ 163,496
Installment notes receivable on manufactured homes, net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Allowance	$ (400)	$ (400)
Receivable with Imputed Interest, Effective Yield (Interest Rate)	8.00%	8.20%
Receivable With Imputed Interest, Term	17 years 2 months 12 days	17 years 2 months 12 days
Carrying Value [Member] | Installment notes receivable on manufactured homes, net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net		$ 115,797
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Installment notes receivable on manufactured homes, net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts and Notes Receivable, Net	$ 124,738

Notes and Other Receivables, 53

Notes and Other Receivables, Schedule of installment notes receivable (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Collateralized receivables, net and Installment Notes Receivables on Manufactured Homes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase to reserve balance	$ 229
Installment notes receivable on manufactured homes, gross [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	116,174
Financed sales of manufactured homes	12,842
Principal payments and payoffs from our customers	(1,912)
Principal reduction from repossessed homes	1,935
Total activity	8,995
Ending balance	$ 125,169

Notes and Other Receivables, Al

Notes and Other Receivables, Allowance for installment notes receivable (Details) - Collateralized receivables, net and Installment Notes Receivables on Manufactured Homes [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 377
Lower of cost or market write-downs	175
Increase to reserve balance	229
Total activity	(54)
Ending balance	$ (431)

Notes And Other Receivables N55

Notes And Other Receivables Notes and Other Receivables, Other receivables - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables for rent, water, sewer usage	$ 12.5	$ 7
Allowance for rent, water, sewer usage receivables	(1.2)	(1.5)
Contract with Customer, Asset, Reclassified to Receivable	28.6	13.8
Insurance receivables	$ 28	$ 26.9

Intangible Assets Intangible 56

Intangible Assets Intangible Assets, Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 135,410	$ 134,888
Accumulated Amortization	(52,168)	(48,436)
Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	32,165	32,165
Accumulated Amortization	$ (1,632)	(1,409)
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Gross Carrying Amount	$ 101,365	100,843
Accumulated Amortization	$ (49,066)	(45,576)
Franchise Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Gross Carrying Amount	$ 1,880	1,880
Accumulated Amortization	$ (1,470)	$ (1,451)
Minimum [Member] | Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Maximum [Member] | Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	57 years

Intangible Assets Intangible 57

Intangible Assets Intangible Assets, Schedule of Intangible Asset Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 3,732	$ 3,802	$ 2,282
Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	223	257	0
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	3,490	3,416	2,153
Franchise Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 19	$ 129	$ 129

Intangible Assets, Intangibles

Intangible Assets, Intangibles Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 10,786
2,018	13,685
2,019	11,957
2,020	11,565
2,021	$ 6,964

Consolidated Variable Interes59

Consolidated Variable Interest Entities, Schedule of Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investment property, net	$ 5,642,654	$ 5,645,354
Other assets, net (including $1,453 and $1,659 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	138,529	134,304
Mortgage loans payable (including $41,756 and $41,970 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	2,826,225	2,867,356
Other liabilities (including $1,326 and $1,468 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	282,993	270,741
Consolidated variable interest entities	$ 4,751	4,285
VIE as a Percentage of Consolidated Assets	0.80%
VIE as a Percentage of Consolidated Liabilities	1.20%
VIE as a Percentage of Total Equity	1.00%
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investment property, net	$ 49,943	50,193
Other assets, net (including $1,453 and $1,659 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	1,453	1,659
Total Assets	51,396	51,852
Mortgage loans payable (including $41,756 and $41,970 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	41,756	41,970
Other liabilities (including $1,326 and $1,468 for consolidated variable interest entities at March 31, 2018 and December 31, 2017; see Note 7)	1,326	1,468
Total Liabilities and Stockholder's Equity	$ 47,833	$ 47,723

Debt And Lines Of Credit , Sche

Debt And Lines Of Credit , Schedule of debt and lines of credit (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Secured debt	$ 2,826,225	$ 2,867,356
Preferred OP units - mandatorily redeemable	$ 37,338
Debt weighted average to maturity, years	8 years 6 months	8 years 10 months 24 days
Weighted average interest rate	4.50%	4.50%
Lines of credit		$ 41,257
Total debt	$ 3,129,440	3,079,238
Collateralized term loans - CMBS [Member]
Debt Instrument [Line Items]
Secured debt	$ 994,605	$ 410,747
Debt weighted average to maturity, years	5 years 6 months	5 years
Weighted average interest rate	4.40%	5.10%
Preferred OP units [Member]
Debt Instrument [Line Items]
Secured debt	$ 37,338
Preferred OP units - mandatorily redeemable		$ 41,443
Debt weighted average to maturity, years	15 years 1 month 6 days	5 years
Weighted average interest rate	10.00%	6.70%
Line of Credit [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.00%
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Debt Instrument [Line Items]
Secured debt	$ 384,910	$ 1,026,014
Debt weighted average to maturity, years	6 years 7 months 6 days	5 years 7 months 6 days
Weighted average interest rate	3.90%	4.40%
Life Companies [Member] | Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Secured debt	$ 1,038,459	$ 1,044,246
Debt weighted average to maturity, years	13 years 8 months 12 days	13 years 10 months 24 days
Weighted average interest rate	3.90%	3.90%
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Debt Instrument [Line Items]
Secured debt	$ 408,251	$ 386,349
Debt weighted average to maturity, years	4 years 9 months 18 days	6 years 10 months 24 days
Weighted average interest rate	5.10%	3.90%
Carrying Value [Member] | Secured borrowing [Member]
Debt Instrument [Line Items]
Secured debt	$ 124,077	$ 129,182
Secured borrowings on collateralized receivables		$ 129,182
Debt weighted average to maturity, years	5 years 4 months 24 days	15 years 3 months 18 days
Weighted average interest rate	6.60%	10.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Lines of credit	$ 141,800
Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Debt weighted average to maturity, years	3 years	3 years 1 month 6 days
Weighted average interest rate	3.00%	2.80%

Debt And Lines Of Credit , Narr

Debt And Lines Of Credit , Narrative - Collateralized Term Loans (Details)	1 Months Ended			3 Months Ended			12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017	Jun. 30, 2017USD ($)	Mar. 31, 2018USD ($)propertiescommunitysites	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)community	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt				$ 196,000	$ 300,000	$ 466,000
Reduction in secured borrowing balance				$ 5,105,000		$ 5,914,000
Number of Real Estate Units Released | community				3		1
Weighted average interest rate	4.50%			4.50%			4.50%
Number of Units in Real Estate Property | properties				0
Debt weighted average to maturity, length				8 years 6 months			8 years 10 months 24 days
Total debt	$ 2,867,356,000			$ 2,826,225,000			$ 2,867,356,000
Secured Debt [Member]
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt				200,000
Reduction in secured borrowing balance				$ 24,400,000
Debt Instrument, Interest Rate, Stated Percentage	4.25%						4.25%
Debt instrument, face amount	$ 100,000,000		$ 77,000,000		$ 77,000,000		$ 100,000,000
Interest rate			4.16%	6.36%	4.16%
Debt instrument term	30 years		25 years
Commercial Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.10%			4.40%			5.10%
Debt weighted average to maturity, length				5 years 6 months			5 years
Total debt	$ 410,747,000			$ 994,605,000			$ 410,747,000
Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Net book value of properties securing collateralized term loans				$ 3,300,000,000
Properties securing debt [Member] | Collateralized Mortgage Backed Securities [Member]
Debt Instrument [Line Items]
Number of Units in Real Estate Property | sites				74,630
Debt Instrument, number of properties securing a debt instument | properties				187
Collateralized Term Loan Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Defeased	38,600,000
Gain (loss) on extinguishment of debt	$ 5,200,000
Debt Instrument, Interest Rate, Stated Percentage	5.25%						5.25%
Collateralized Term Loan Due August 31, 2017 [Member]
Debt Instrument [Line Items]
Reduction in secured borrowing balance			$ 3,900,000
Debt Instrument, Interest Rate, Stated Percentage			6.54%		6.54%
Collateralized Term Loan Due August 1, 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Defeased						$ 18,900,000
Debt Instrument, Interest Rate, Stated Percentage	6.49%						6.49%
Collateralized Term Loan Due May 1, 2017 [Member]
Debt Instrument [Line Items]
Reduction in secured borrowing balance						$ 10,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.57%						5.57%
Ocean West [Member]
Debt Instrument [Line Items]
Number of Units in Real Estate Property | sites				130
Ocean West [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 4,600,000
Interest rate				4.34%
Debt instrument term		9 years 9 months 18 days

Debt And Lines Of Credit , Na62

Debt And Lines Of Credit , Narrative - Aspen Preferred OP Units and Series B-3 preferred OP units (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Debt Instrument [Line Items]
Stock Redeemed or Called During Period, Shares		3,400,000
Stock Redeemed or Called During Period, Value		$ 85.5
Preferred OP units [Member] | Convertible debt - Aspen Preferred OP Units January 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 34.7
Convertible units to shares (in shares)	463,652
Debt Instrument, Interest Rate During Period	6.50%
Debt Instrument, Convertible, Conversion Price	$ 68		$ 27
Conversion of Stock, Shares Converted	0.397
Series B-3 Preferred OP Units [Member] | Convertible debt - Aspen Preferred OP Units January 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 2.7	$ 6.7
Debt Instrument, Convertible, Conversion Price	$ 100
Series B-3 Preferred OP Units [Member]
Debt Instrument [Line Items]
Stock Redeemed or Called During Period, Shares	41,051
Redemption price including accrued and unpaid dividends (in dollars per share)	$ 100.065753
Stock Redeemed or Called During Period, Value	$ 4.1

Debt And Lines Of Credit , Na63

Debt And Lines Of Credit , Narrative - Line of Credit (Details)	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2017	Mar. 31, 2018USD ($)communityRate	Mar. 31, 2017community	Dec. 31, 2017USD ($)	Apr. 25, 2017USD ($)Rate	Apr. 24, 2017USD ($)
Line of Credit Facility [Line Items]
Lines of credit				$ 41,257,000
Weighted average interest rate		4.50%		4.50%
Debt weighted average to maturity, length		8 years 6 months		8 years 10 months 24 days
Number of Real Estate Units Released | community		3	1
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity					$ 650,000,000	$ 450,000,000
Line of credit, borrowing capacity					1,000,000,000
Debt Instrument, Maturity Date	Apr. 25, 2021
Line of credit, additional borrowing capacity					350,000,000
Letters of credit outstanding, amount		$ 1,300,000
Weighted average interest rate		3.00%
Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity		$ 12,000,000
Lines of credit		$ 2,300,000		$ 4,000,000
Weighted average interest rate | Rate		7.00%
Prime Rate [Member] | Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Basis points | Rate		100.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity					550,000,000
Long-term Debt		$ 40,000,000
Lines of credit		$ 141,800,000
Revolving Credit Facility [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate		3.00%		2.80%
Debt weighted average to maturity, length		3 years		3 years 1 month 6 days
Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of credit variable interest rate | Rate		1.35%
Term Loan [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity					$ 100,000,000
Long-term Debt		$ 100,000,000
Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of credit variable interest rate | Rate		1.30%
Line of Credit [Member]
Line of Credit Facility [Line Items]
Long-term Debt		$ 140,000,000
Minimum [Member] | Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					1.35%
Minimum [Member] | Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					1.30%
Maximum [Member] | Prime Rate [Member] | Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate		6.00%
Maximum [Member] | Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					2.20%
Maximum [Member] | Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					2.15%

Equity and Mezzanine Securiti64

Equity and Mezzanine Securities, Narrative (Details) - USD ($)

Apr. 16, 2018

Apr. 02, 2018

Jun. 17, 2015

Apr. 24, 2018

Sep. 30, 2017

Jun. 30, 2017

May 31, 2017

Mar. 31, 2018

Dec. 31, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2017

Nov. 30, 2004

Class of Stock [Line Items]

Shares Issued, Weighted Average Price Per Share

$ 85.01

$ 93.33

$ 85.01

$ 76.47

$ 93.33

Aggregate Value of Shares to be Issued in Accordance to Sales Agreement

$ 450,000,000

Commission, Maximum Percentage of Gross Sales Price Per Share According to Sales Agreement

2.00%

New shares issued (in shares)

4,830,000

321,800

400,000

280,502

Shares Issued, Price Per Share

$ 86

Proceeds from Issuance of Common Stock

$ 408,900,000

Redemption price (in dollars per share)

$ 25

$ 25.14349

$ 25.14349

Stock Redeemed or Called During Period, Shares

3,400,000

Stock Redeemed or Called During Period, Value

$ 85,500,000

Share Price

$ 87.24

Total consideration transferred

$ 2,000,000

$ 144,730,000

Subsequent Event

Class of Stock [Line Items]

New shares issued (in shares)

220,000

Proceeds from Issuance of Common Stock

$ 19,800,000

Share Price

$ 91.31

Series A-4 Preferred Stock

Class of Stock [Line Items]

Preferred Stock, Dividends Per Share, Declared

$ 0.40625

Stock Redeemed or Called During Period, Shares

438,448

Series A-4 Preferred Stock | Subsequent Event

Class of Stock [Line Items]

Payments of dividends

$ 440,900

Common Stock

Class of Stock [Line Items]

Dividends per common share

$ 0.71

Common Stock | Subsequent Event

Class of Stock [Line Items]

Payments of dividends

$ 56,014,000

Common OP Units

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

Class of Stock [Line Items]

Stock Redeemed or Called During Period, Shares

200,000

Common Stock

Class of Stock [Line Items]

Authorized to be repurchased (in shares)

1,000,000

Remaining number of shares authorized to be repurchased (in shares)

400,000

Series A-4 preferred OP units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

2,373,000

2,000,000

Series A-4 preferred OP units | Common OP Units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

1,054,000

888,000

Conversion of Common OP Units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

6,777

8,579

Conversion of Common OP Units | Common OP Units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

6,777

Series A-1 Preferred OP Units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

3,700,000

5,425,000

Series A-1 Preferred OP Units | Common OP Units

Class of Stock [Line Items]

Conversion of Common OP Units to common stock (in shares)

9,023,000

13,230,000

Pismo Dunes [Member]

Class of Stock [Line Items]

Total consideration transferred

$ 26,400,000

$ 21,920,000

Pismo Dunes [Member] | Common OP Units

Class of Stock [Line Items]

Business Acquisition, Equity Interest Issued or Issuable, Number of Shares

298,900

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

Equity and Mezzanine Securiti65

Equity and Mezzanine Securities, Conversion of Stock (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Conversion of Stock [Line Items]
Redemption price (in dollars per share)	$ 25	$ 25.14349
Stock Redeemed or Called During Period, Value		$ 85.5
Stock Redeemed or Called During Period, Shares		3,400,000
Conversion of Common OP Units
Conversion of Stock [Line Items]
Conversion of units	6,777		8,579
Series A-1 Preferred OP Units
Conversion of Stock [Line Items]
Conversion of units	3,700,000		5,425,000
Series A-4 preferred OP units
Conversion of Stock [Line Items]
Conversion of units	2,373,000		2,000,000
Series A-4 Preferred Stock
Conversion of Stock [Line Items]
Conversion of units	0		45,153,000
Series C preferred OP unit
Conversion of Stock [Line Items]
Conversion of units	0		4,993,000
Common OP Units | Conversion of Common OP Units
Conversion of Stock [Line Items]
Conversion Rate	1,000
Conversion of units	6,777
Common OP Units | Series A-1 Preferred OP Units
Conversion of Stock [Line Items]
Conversion Rate	2,439
Conversion of units	9,023,000		13,230,000
Common OP Units | Series A-4 preferred OP units
Conversion of Stock [Line Items]
Conversion Rate	444.4000
Conversion of units	1,054,000		888,000
Common OP Units | Series A-4 Preferred Stock
Conversion of Stock [Line Items]
Conversion Rate	444.4000
Conversion of units	0		20,068,000
Common OP Units | Series C preferred OP unit
Conversion of Stock [Line Items]
Conversion Rate	1,110
Conversion of units	0		5,539,000

Equity and Mezzanine Securiti66

Equity and Mezzanine Securities Equity and Mezzanine Securities, Dividends Payable Table (Details) - USD ($)	Apr. 16, 2018	Apr. 02, 2018	Mar. 29, 2018	Mar. 16, 2018	Mar. 31, 2018
Common Stock
Dividends Payable [Line Items]
Dividends Payable, Date of Record			Mar. 29, 2018
Dividends per common share					$ 0.71
Series A-4 Preferred Stock
Dividends Payable [Line Items]
Dividends Payable, Date of Record				Mar. 16, 2018
Preferred Stock, Dividends Per Share, Declared					$ 0.40625
Subsequent Event | Common Stock
Dividends Payable [Line Items]
Dividends Payable, Date to be Paid	Apr. 16, 2018
Payments of dividends	$ 56,014,000
Subsequent Event | Series A-4 Preferred Stock
Dividends Payable [Line Items]
Dividends Payable, Date to be Paid		Apr. 2, 2018
Payments of dividends		$ 440,900

Equity and Mezzanine Securiti67

Equity and Mezzanine Securities Equity and Mezzanine Securities, Schedule of Sale of Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017
Aggregate Value of Shares to be Issued in Accordance to Sales Agreement		$ 450
Share Price		$ 87.24
Proceeds from Issuance of Common Stock	$ 408.9
New shares issued (in shares)	4,830,000		321,800	400,000	280,502
Shares Issued, Price Per Share	$ 86
Shares Issued, Weighted Average Price Per Share			$ 93.33	$ 85.01	$ 76.47
Issuance of common stock and common OP units, net			$ 29.7	$ 33.6	$ 21.2

Share-Based Compensation (Detai

Share-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price	$ 87.24
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Percentage	74.80%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	90,000
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercises in period		1,500
Proceeds from stock option exercise		$ 0.1
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested restricted stock (in shares)	93,647
Grant One [Member] | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)	16,500
Weighted average grant date fair value	$ 88.30
Grant One [Member] | Third Anniversary | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	35.00%
Grant One [Member] | Fourth Anniversary | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	35.00%
Grant One [Member] | Fifth Anniversary | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	20.00%
Grant One [Member] | Sixth Anniversary | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	5.00%
Grant One [Member] | Seventh Anniversary | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage	5.00%
Grant Two [Member] | Key Employees [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)	44,600
Weighted average grant date fair value	$ 85.29
Grant Three [Member] | Executive Officer [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)	60,000
Weighted average grant date fair value	$ 87.24
Grant Four [Member] | Executive Officer [Member] | Restricted Stock [Member] | 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)	90,000
Weighted average grant date fair value	$ 65.24
Award vesting percentage	100.00%
Grant Five [Member] | Director [Member] | Restricted Stock [Member] | 2004 Non-employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)	16,800
Weighted average grant date fair value	$ 85.28
Award vesting percentage	100.00%

Segment Reporting Segment Repor

Segment Reporting Segment Reporting, Seasonality (Details) $ in Millions	3 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Segment Reporting Information [Line Items]
Number of reportable segments | segment				2
Real Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Expected annual transient RV revenue | $				$ 85.5	$ 78
Transient RV rental revenue recognized as a percentage				25.80%	15.80%	36.90%	20.10%	27.20%
Scenario, Forecast [Member] | Real Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Transient RV rental revenue recognized as a percentage	16.20%	37.40%	20.60%

Segment Reporting Results of Op

Segment Reporting Results of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 251,699		$ 228,875
Operating expenses/Cost of sales	102,473		90,962
Net operating income/Gross profit	149,226		137,913
Interest and other revenues, net	6,217		5,525
Home selling expenses	(3,290)		(3,111)
General and administrative	(19,931)		(17,932)
Transaction costs	0		(2,386)
Depreciation and amortization	(66,437)		(62,766)
Extinguishment of debt	(196)	$ (300)	(466)
Interest	(31,138)		(31,322)
Interest on mandatorily redeemable preferred OP units	(619)		(784)
Catastrophic weather related charges	2,213		87
Other (expense) / income, net	(2,617)		839
Current tax expense	(174)		(178)
Deferred tax benefit	347		300
Net income	33,601		25,545
Less: Preferred return to Series A-1 preferred OP units	1,080		1,174
Less: Amounts attributable to noncontrolling interests	2,094		1,088
Net income attributable to Sun Communities, Inc.	30,427		23,283
Less: Preferred stock distributions	441		2,179
Net income attributable to Sun Communities, Inc. common stockholders	29,986		21,104
Real Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Revenues	203,779		189,273
Operating expenses/Cost of sales	70,732		64,977
Net operating income/Gross profit	133,047		124,296
Interest and other revenues, net	6,276		5,525
Home selling expenses	0		0
General and administrative	(17,187)		15,721
Transaction costs	0		(2,411)
Depreciation and amortization	(50,508)		47,330
Extinguishment of debt	(196)		(466)
Interest	(31,134)		31,319
Interest on mandatorily redeemable preferred OP units	(619)		784
Catastrophic weather related charges	(2,357)		(87)
Other (expense) / income, net	(2,616)		631
Current tax expense	(96)		123
Deferred tax benefit	347		(300)
Net income	39,671		32,511
Less: Preferred return to Series A-1 preferred OP units	1,080		1,174
Less: Amounts attributable to noncontrolling interests	2,400		1,483
Net income attributable to Sun Communities, Inc.	36,191		29,854
Less: Preferred stock distributions	441		2,179
Net income attributable to Sun Communities, Inc. common stockholders	35,750		27,675
Home Sales and Home Rentals Segment [Member]
Segment Reporting Information [Line Items]
Revenues	47,920		39,602
Operating expenses/Cost of sales	31,741		25,985
Net operating income/Gross profit	16,179		13,617
Interest and other revenues, net	(59)		0
Home selling expenses	(3,290)		3,111
General and administrative	(2,744)		2,211
Transaction costs	0		(25)
Depreciation and amortization	(15,929)		15,436
Extinguishment of debt	0		0
Interest	(4)		3
Interest on mandatorily redeemable preferred OP units	0		0
Catastrophic weather related charges	144		0
Other (expense) / income, net	(1)		208
Current tax expense	(78)		55
Deferred tax benefit	0		0
Net income	(6,070)		(6,966)
Less: Preferred return to Series A-1 preferred OP units	0		0
Less: Amounts attributable to noncontrolling interests	(306)		(395)
Net income attributable to Sun Communities, Inc.	(5,764)		(6,571)
Less: Preferred stock distributions	0		0
Net income attributable to Sun Communities, Inc. common stockholders	$ (5,764)		$ (6,571)

Segment Reporting Identifiable

Segment Reporting Identifiable Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	$ 5,642,654	$ 5,645,354
Cash and cash equivalents	15,153	10,127	$ 10,919	$ 8,164
Inventory of manufactured homes	36,311	30,430
Notes and other receivables, net	193,851	163,496
Collateralized receivables, net	123,155	128,246
Other assets	138,529	134,304
TOTAL ASSETS	6,149,653	6,111,957
Real Property Operations Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	5,162,460	5,172,521
Cash and cash equivalents	(1,483)	(7,649)
Inventory of manufactured homes	0	0
Notes and other receivables, net	177,247	149,798
Collateralized receivables, net	123,155	128,246
Other assets	133,489	130,455
TOTAL ASSETS	5,594,868	5,573,371
Home Sales and Home Rentals Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Investment property, net	480,194	472,833
Cash and cash equivalents	16,636	17,776
Inventory of manufactured homes	36,311	30,430
Notes and other receivables, net	16,604	13,698
Collateralized receivables, net	0	0
Other assets	5,040	3,849
TOTAL ASSETS	$ 554,785	$ 538,586

Income Taxes , Narrative (Detai

Income Taxes , Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Loss Carryforwards [Line Items]
Minimum Percent of Income From Qualifying Sources to Allow For Real Estate Investment Trust Classification	95.00%
Required Minimum Percent of Taxable Income Distributed to Stock Holders	90.00%
Provision for state income taxes	$ 200	$ (178)
Deferred Income Tax Expense (Benefit)	(347)	$ (300)
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Gross	21,600
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Liabilities, Gross	$ 100

Earnings Per Share , Calculatio

Earnings Per Share , Calculation of Numerator and Denominator (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator
Net income attributable to common stockholders	$ 29,986	$ 21,104
Allocation to restricted stock awards	(303)	(253)
Basic earnings: Net income attributable to common stockholders after allocation	29,683	20,851
Allocation to restricted stock awards	303	253
Diluted earnings: Net income attributable to common stockholders after allocation	$ 29,986	$ 21,104
Denominator
Weighted average common shares outstanding	78,855	72,677
Add: dilutive stock options	2	2
Add: dilutive restricted stock	607	441
Diluted weighted average common shares and securities	79,464	73,120
Basic	$ 0.38	$ 0.29
Diluted	$ 0.38	$ 0.29

Earnings Per Share , Antidiluti

Earnings Per Share , Antidilutive Securities Excluded from Computation of Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	6,228	7,033
Common OP Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	2,739	2,750
Series A-1 Preferred OP Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	342	362
Series A-3 Preferred OP Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	40	40
Series A-4 preferred OP units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	422	632
Series A-4 Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,085	1,637
Series C preferred OP units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	316	328
Aspen Preferred OP Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	1,284	1,284

Derivative Instruments And He75

Derivative Instruments And Hedging Activities , Derivative Contracts (Details)	3 Months Ended
	Mar. 31, 2018USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Fair Value, Net	$ 0
Interest Rate Cap [Member] | Derivative maturing 2018 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Type	Cap
Derivative, Purpose	Cap Floating Rate
Derivative, Effective Date	Apr. 1, 2015
Derivative, Maturity Date	Apr. 1, 2018
Notional Amount of Derivatives	$ 150,100,000
Derivative, Variable Rate	3.564%
Derivative, Fixed Rate	9.00%
Derivative, Spread on Variable Rate	0.00%
Interest Rate Cap [Member] | Derivative Maturing 2023 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Type	Cap
Derivative, Purpose	Cap Floating Rate
Derivative, Effective Date	Oct. 3, 2016
Derivative, Maturity Date	May 1, 2023
Notional Amount of Derivatives	$ 9,600,000
Derivative, Variable Rate	4.364%
Derivative, Fixed Rate	11.02%
Derivative, Spread on Variable Rate	0.00%

Fair Value of Financial Instr76

Fair Value of Financial Instruments , By Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financial assets
Notes and other receivables, net	$ 193,851	$ 163,496
Collateralized receivables, net	123,155	128,246
Financial liabilities
Secured debt	2,826,225	2,867,356
Lines of credit		41,257
Carrying Value [Member]
Financial liabilities
Debt (excluding secured borrowings)	2,863,563	2,908,799
Lines of credit		41,257
Other liabilities (contingent consideration)	7,069	6,976
Carrying Value [Member] | Installment notes receivable on manufactured homes, net [Member]
Financial assets
Notes and other receivables, net		115,797
Carrying Value [Member] | Collateralized Receivables [Member]
Financial assets
Notes and other receivables, net	123,200	128,246
Carrying Value [Member] | Secured Debt [Member]
Financial liabilities
Secured borrowings on collateralized receivables		129,182
Secured debt	124,077	129,182
Carrying Value [Member] | Secured Debt [Member] | Fair Value, Measurements, Recurring [Member]
Financial liabilities
Secured borrowings on collateralized receivables		129,182
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Financial liabilities
Debt (excluding secured borrowings)	2,641,997	2,726,770
Secured borrowings on collateralized receivables	124,077
Secured debt		129,182
Lines of credit	141,800
Lines of credit		41,257
Other liabilities (contingent consideration)	7,069	6,976
Estimate of Fair Value Measurement [Member] | Installment notes receivable on manufactured homes, net [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets
Notes and other receivables, net	124,738
Receivables		115,797
Estimate of Fair Value Measurement [Member] | Collateralized Receivables [Member] | Fair Value, Measurements, Recurring [Member]
Financial assets
Receivables		$ 128,246
Collateralized receivables, net	$ 123,155

Recent Accounting Pronounceme77

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Cash and cash equivalents	$ 15,153	$ 10,127	$ 10,919	$ 8,164
Restricted cash	12,271	13,382	15,791	17,149
Cash, cash equivalents and restricted cash	$ 27,424	$ 23,509	$ 26,710	$ 25,313

Commitments And Contingencies C

Commitments And Contingencies Commitments And Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Loss Contingencies [Line Items]
Total estimated insurance receivable - December 31, 2017	$ 23,700
Change in estimated insurance recoveries	6,000
Advances from insurer	(5,000)
Total estimated insurance receivable - March 31, 2018	24,700
Loss Contingency Accrual [Roll Forward]
Loss Contingency Accrual	31,700
Loss Contingency Accrual, Period Increase (Decrease)	3,800
Loss Contingency Accrual	35,500
Catastrophic weather related charges	(2,213)	$ (87)
Loss from Catastrophes [Member]
Loss Contingencies [Line Items]
Total estimated insurance receivable - December 31, 2017	23,700
Change in estimated insurance recoveries	6,000
Advances from insurer	(5,000)
Total estimated insurance receivable - March 31, 2018	24,700
Loss Contingency Accrual [Roll Forward]
Loss Contingency Accrual	21,300
Loss Contingency Accrual, Period Increase (Decrease)	3,800
Loss Contingency Accrual	25,100
Loss Of Earnings [Member]
Loss Contingencies [Line Items]
Total estimated insurance receivable - December 31, 2017	0
Change in estimated insurance recoveries	0
Advances from insurer	0
Total estimated insurance receivable - March 31, 2018	0
Impaired Assets [Member]
Loss Contingency Accrual [Roll Forward]
Loss Contingency Accrual	10,400
Loss Contingency Accrual, Period Increase (Decrease)	0
Loss Contingency Accrual	10,400
Redevelopment Costs In Excess Of Impairment Charges [Member]
Loss Contingencies [Line Items]
Total estimated insurance receivable - December 31, 2017	0
Change in estimated insurance recoveries	0
Advances from insurer	0
Total estimated insurance receivable - March 31, 2018	$ 0

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended
	Apr. 24, 2018	May 31, 2017	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Mar. 31, 2018
Subsequent Event [Line Items]
New shares issued (in shares)		4,830,000	321,800	400,000	280,502
Share Price						$ 87.24
Proceeds from Issuance of Common Stock		$ 408.9
Subsequent Event
Subsequent Event [Line Items]
New shares issued (in shares)	220,000
Share Price	$ 91.31
Proceeds from Issuance of Common Stock	$ 19.8