Document and Entity Information Statement [Table] Statement [Line Items] Statement Document Type Document Quarterly Report Document Transition Report Document Period End Date Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Central Index Key Amendment Flag CONSOLIDATED BALANCE SHEETS Assets [Abstract] ASSETS Real Estate Investment Property, at Cost Storage properties Storage properties Real Estate Investment Property, Accumulated Depreciation Less: Accumulated depreciation Real Estate Investment Property, Net Storage properties Storage facilities, net Storage properties, net (including VIE assets of $86,409 and $92,612, respectively) Net book value of self-storage facilities Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Restricted Cash and Cash Equivalents Restricted cash Deferred Finance Costs, Net Less: Loan procurement costs, net Loan procurement costs, net of amortization Equity Method Investments Investment in real estate ventures, at equity Investment in real estate entities Other Assets Other assets, net Assets Total assets Liabilities and Equity [Abstract] LIABILITIES AND CAPITAL LIABILITIES AND EQUITY Represents the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized senior notes net of discounts, with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. Unsecured Senior Notes, Net Unsecured senior notes, net Total unsecured senior notes, net Long-term Line of Credit Revolving credit facility Notes and Loans Payable Total mortgage loans and notes payable Mortgage loans and notes payable, net Total mortgage loans and notes payable, net Accounts Payable and Accrued Liabilities Accounts payable, accrued expenses and other liabilities Accounts payable, accrued expenses and other liabilities Dividends Payable Distributions payable Deferred Revenue Deferred revenue This element represents payments received from purchasers from the sale of real estate prior to the closing date. Real Estate Security Deposit Liability Security deposits Liabilities Total liabilities Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest Balance of Noncontrolling Interests in the Operating Partnership Balance of Noncontrolling Interests in the Operating Partnership Limited Partnership interests of third parties Noncontrolling interests in the Operating Partnership Commitments and Contingencies. Commitments and contingencies Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Equity Common Stock, Value, Issued Common shares $.01 par value, 400,000,000 shares authorized, 193,748,023 and 193,557,024 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively Additional Paid in Capital Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax Ending balance Beginning balance Accumulated other comprehensive loss Retained Earnings (Accumulated Deficit) Accumulated deficit Stockholders' Equity Attributable to Parent Total CubeSmart shareholders' equity Stockholders' Equity Attributable to Noncontrolling Interest Noncontrolling interests in subsidiaries Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Balance Balance Total equity Liabilities and Equity Total liabilities and equity Common Stock, Par or Stated Value Per Share Common shares, par value (in dollars per share) Common Stock, Shares Authorized Common shares, shares authorized Common Stock, Shares, Issued Common shares, shares issued Common Stock, Shares, Outstanding Common shares, shares outstanding CONSOLIDATED STATEMENTS OF OPERATIONS Revenues [Abstract] REVENUES Operating Lease, Lease Income Rental income Management Fees Revenue Property related income Revenues Total revenues Costs and Expenses [Abstract] OPERATING EXPENSES Cost of Revenue Property operating expenses Depreciation, Depletion and Amortization Depreciation and amortization General and Administrative Expense General and administrative Costs and Expenses Total operating expenses Nonoperating Income (Expense) [Abstract] OTHER (EXPENSE) INCOME Interest Expense [Abstract] Interest: Interest Expense, Debt Interest expense on loans Amortization of Financing Costs Loan procurement amortization expense Income (Loss) from Equity Method Investments Equity in losses (earnings) of real estate ventures Equity in (losses) earnings of real estate ventures Company's share of net (loss) income Other Nonoperating Income (Expense) Other Other income or expenses related to interest expense on loans, amortization of financing costs, investment income, business combination costs and other costs not specifically identified in the taxonomy. Other Nonoperating Income (Expense), Net Total other expense Net Income (Loss), Including Portion Attributable to Noncontrolling Interest NET INCOME NET INCOME Net income Net Income (Loss) Attributable to Noncontrolling Interest [Abstract] NET (INCOME) LOSS ATTRIBUTABLE TO NONCONTROLLING INTERESTS Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable Noncontrolling interests in the Operating Partnership Operating Partnership interests of third parties Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Redeemable Noncontrolling interest in subsidiaries Net Income (Loss) Available to Common Stockholders, Basic NET INCOME ATTRIBUTABLE TO THE COMPANY'S COMMON SHAREHOLDERS Earnings Per Share, Basic Basic earnings per share attributable to common shareholders (in dollars per share) Earnings Per Share, Diluted Diluted earnings per share attributable to common shareholders (in dollars per share) Weighted Average Number of Shares Outstanding, Basic Weighted-average basic units outstanding (in units) Weighted average basic shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Weighted-average diluted units outstanding (in units) Weighted average diluted shares outstanding (in shares) CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income: Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Unrealized gains on interest rate swaps Represents net of tax amount of the income statement impact of the reclassification adjustment of accumulated gain (loss) from interest rate swap agreements designated and qualifying as the effective portion of cash flow hedges realized in net income. Also includes reclassification adjustments of an entity's share of an equity investee's deferred hedging gain (loss) realized in net income. Other Comprehensive Income (Loss) Reclassification Adjustment on Interest Rate Swap Agreements Included in Net Income Net of Tax Reclassification of realized losses on interest rate swaps Other Comprehensive Income (Loss), Net of Tax OTHER COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest COMPREHENSIVE INCOME This element represents Comprehensive Income (Loss), Net of Tax, Attributable to Redeemable Noncontrolling Interest. Comprehensive Income, Net of Tax, Attributable to Redeemable Noncontrolling Interest Comprehensive income attributable to noncontrolling interests in the Operating Partnership Comprehensive income attributable to Operating Partnership interests of third parties Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests, excluding redeemable noncontrolling interest. Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest, Excluding the Redeemable Noncontrolling Interest Comprehensive (income) loss attributable to noncontrolling interest in subsidiaries Comprehensive Income (Loss), Net of Tax, Attributable to Parent COMPREHENSIVE INCOME ATTRIBUTABLE TO THE COMPANY CONSOLIDATED STATEMENTS OF EQUITY Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent [Member] Total Shareholders' Equity Common Stock [Member] Common Shares Additional Paid In Capital [Member] Additional Paid-in Capital Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive (Loss) Income Retained Earnings [Member] Accumulated Deficit Noncontrolling Interest [Member] Noncontrolling Interest in Subsidiaries The axis of temporary equity. Temporary Equity [Axis] Temporary equity reported by a business entity. Temporary Equity [Domain] Temporary Equity [Domain] This element represents that portion of equity (net assets) in an operating partnership not attributable, directly or indirectly, to the parent. Temporary Equity [Member] Noncontrolling Interests in Operating Partnership Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity Shares, Issued Balance (in shares) Balance (in shares) Noncontrolling Interest, Increase from Subsidiary Equity Issuance Contributions from noncontrolling interests in subsidiaries Reduction to additional paid in capital Contributions from noncontrolling interests in subsidiaries Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Distributions paid to noncontrolling interests in subsidiaries Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Acquisition of noncontrolling interest in subsidiary Elimination of noncontrolling interest in subsidiaries due to acquisition Acquisition of noncontrolling interest Stock Issued During Period, Value, New Issues Issuance of common shares Stock Issued During Period, Shares, New Issues Issuance of common shares (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Issuance of restricted shares (in shares) Represents the value of the operating units issued during the period. Stock Issued During Period Operating Units Issuance of OP Shares Issuance of OP units Stock Issued During Period, Value, Conversion of Units Conversion from units to shares Stock Issued During Period, Shares, Conversion of Units Conversion from units to shares (in shares) Stock Issued During Period, Value, Stock Options Exercised Exercise of stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options (in shares) This element represents the amount of amortization of restricted shares during the period. Adjustments to Additional Paid in Capital, Amortization of Restricted Stock Amortization of restricted shares Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Share compensation expense Noncontrolling Interest, Change in Redemption Value Adjustment for noncontrolling interest in the Operating Partnership Adjustment for Operating Partnership interests of third parties Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Net income (loss) Temporary Equity, Net Income Net income (loss) Amount after tax and reclassification adjustments of other comprehensive income (loss), including portion attributable to temporary equity. Other Comprehensive Income (Loss), Net of Tax Including Portion Attributable to Temporary Equity Other comprehensive income, net Amount after tax and reclassification adjustments of other comprehensive income (loss), attributable to temporary equity. Other Comprehensive Income (Loss), Net of Tax, Attributable to Temporary Equity Other comprehensive income, net Dividends, Common Stock Common share distributions Common Stock, Dividends, Per Share, Declared Common share distributions (in dollars per share) CONSOLIDATED STATEMENTS OF CASH FLOWS Net Cash Provided by (Used in) Operating Activities [Abstract] Operating Activities Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to cash provided by operating activities: The cash flow impact of the aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. Depreciation, Depletion and Amortization Cash Flow Impact Depreciation and amortization Share-based Compensation Equity compensation expense Amount of income (expense) related to adjustment to fair value of debt. Fair Value Adjustment of Debt Accretion of fair market value adjustment of debt Increase (Decrease) in Operating Capital [Abstract] Changes in other operating accounts: Increase (Decrease) in Other Operating Assets Other assets Increase (Decrease) in Accounts Payable and Accrued Liabilities Accounts payable and accrued expenses Increase (Decrease) in Other Operating Liabilities Other liabilities Net Cash Provided by (Used in) Operating Activities Net cash provided by operating activities Net Cash Provided by (Used in) Investing Activities [Abstract] Investing Activities Payments to Acquire Real Estate Acquisitions of storage properties Acquisitions of storage facilities Payments for additions and improvements to real estate assets. Payments for Additions and Improvements to Real Estate Additions and improvements to storage properties Payments to Develop Real Estate Assets Development costs Payments to Acquire Businesses, Net of Cash Acquired Cash paid for partner's interest in real estate venture, net of cash, cash equivalents and restricted cash acquired Distributions Payable to Real Estate Partnerships Investment in real estate ventures Proceeds from Distributions Received from Real Estate Partnerships Cash distributed from real estate ventures Proceeds from Sale of Real Estate Held-for-investment Proceeds from sale of real estate, net Proceeds from sale of real estate, net Proceeds from Divestiture of Real Estate Partnership Cash distributed from real estate ventures Net Cash Provided by (Used in) Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Financing Activities No definition available. Financing Activities Proceeds from Debt [Abstract] Proceeds from: Proceeds from Issuance of Senior Long-term Debt Unsecured senior notes Proceeds from Lines of Credit Revolving credit facility No definition available. Financing Activities Principal Payments on Debt [Abstract] Principal payments on: Repayments of Lines of Credit Revolving credit facility Repayments of Unsecured Debt Unsecured term loans The cash outflow used to purchase loans that are secured with real estate mortgage and from a borrowing supported by a written promise to pay an obligation. Payments of Mortgage Loans and Notes Payable Mortgage loans and notes payable Payments of Loan Costs Loan procurement costs Payments for Hedge, Financing Activities Settlement of hedge transactions Settlement of hedge transactions Cash outflow related to the acquisition of noncontrolling shareholders' interests. Payments to Acquire Noncontrolling Interests Acquisition of noncontrolling interest in subsidiary, net Proceeds from Issuance of Common Stock Proceeds from issuance of common shares, net Payments Related to Tax Withholding for Share-based Compensation Cash paid upon vesting of restricted shares Cash paid upon vesting of restricted OP units Proceeds from Stock Options Exercised Exercise of stock options Proceeds from Noncontrolling Interests Contributions from noncontrolling interests in subsidiaries Payments to Noncontrolling Interests Distributions paid to noncontrolling interests in subsidiaries Payments of Ordinary Dividends, Common Stock Distributions paid to common OP unitholders Distributions paid to common shareholders The cash outflow to return capital to noncontrolled interest in operating partnership. Payments to Minority Shareholders in Operating Partnership Distributions paid to noncontrolling interests in Operating Partnership Net Cash Provided by (Used in) Financing Activities Net cash (used in) provided by financing activities Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Change in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Cash, cash equivalents and restricted cash at beginning of period Supplemental Cash Flow and Noncash Information [Abstract] Supplemental Cash Flow and Noncash Information Interest Paid, Net Cash paid for interest, net of interest capitalized Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of noncash activities: The amount of [noncash or part noncash] consideration for acquisition of property. Noncash or Part Noncash Acquisition, Properties Acquired Acquisitions of storage properties Escrow Deposits Related to Property Sales Proceeds held in escrow from real estate venture's sale of real estate (see note 4) Escrow Deposit Disbursements Related to Property Acquisition Noncash consideration for acquisition of partner's interest in real estate venture (see note 4) Debt Instrument, Unamortized Discount Discount on issuance of unsecured senior notes The fair value of line of credit drawdown in noncash investing or financing activities. Line of Credit, Non-cash Drawdown Noncash drawdown on revolving credit facility The value of unsecured term loan reduction in noncash investing or financing transactions. Unsecured Term Loan Reduction Repayment of unsecured term loan through noncash drawdown on revolving credit faciltiy This element represents the amount of accretion of liability in noncash investing or financing activities. Accretion Of Liability Accretion of put liability Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Derivative valuation adjustment Derivative valuation adjustment Debt Issuance Costs Incurred During Noncash or Partial Noncash Transaction Loan procurement costs The value of OP units issued. Noncash or Part Noncash Acquisition, Issuance of O P Units Issuance of OP units (see Note 4) Acquisition of noncontrolling interest in subsidiary. Acquisition of Noncontrolling Interest in Subsidiary Acquisition of noncontrolling interest in subsidiary Contributions from noncontrolling interests in subsidiaries. Contributions From Noncontrolling Interests in Subidiaries Contributions from noncontrolling interests in subsidiaries ORGANIZATION AND NATURE OF OPERATIONS Description containing the entire organization and consolidation of financial statements disclosure. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements. Organization and Consolidation of Financial Statements Disclosure [Text Block] ORGANIZATION AND NATURE OF OPERATIONS SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation and Significant Accounting Policies [Text Block] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES