Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Consolidation	Basis of Consolidation. We are the sole general partner of the Operating Partnership and possess full legal control and authority over the operations of the Operating Partnership. As of September 30, 2016 and December 31, 2015, we owned a majority of the partnership interests in the Operating Partnership. Consequently, the accompanying consolidated financial statements include the accounts of the Operating Partnership. All significant inter-company balances have been eliminated. Noncontrolling interests in the accompanying consolidated financial statements represents the share of equity and earnings of the Operating Partnership allocable to holders of partnership interests other than us. Net income or loss is allocated to noncontrolling interests based on the weighted average percentage ownership of the Operating Partnership during the period. Issuance of additional common shares of beneficial interest in Whitestone (the “common shares”) and units of limited partnership interest in the Operating Partnership that are convertible into cash or, at our option, common shares on a one-for-one basis (the “OP units”) changes the ownership interests of both the noncontrolling interests and Whitestone.
Basis of Accounting	Basis of Accounting. Our financial records are maintained on the accrual basis of accounting whereby revenues are recognized when earned and expenses are recorded when incurred.
Use of Estimates	Use of Estimates. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates that we use include the estimated fair values of properties acquired, the estimated useful lives for depreciable and amortizable assets and costs, the estimated allowance for doubtful accounts, the estimated fair value of interest rate swaps and the estimates supporting our impairment analysis for the carrying values of our real estate assets. Actual results could differ from those estimates.
Reclassifications	Reclassifications. We have reclassified certain prior period amounts in the accompanying consolidated financial statements in order to be consistent with the current period presentation. During the nine months ended September 30, 2016, we reclassified certain deferred financing costs, previously classified as an asset as a direct reduction from the carrying amount of certain debt liabilities for all periods presented. Deferred financing costs related to our unsecured line of credit have not been reclassified. See Note 6 for additional information. These reclassifications had no effect on net income or equity.
Marketable Securities	Marketable Securities. We classify our existing marketable equity securities as available-for-sale in accordance with the Financial Accounting Standards Board's (“FASB”) Investments-Debt and Equity Securities guidance. These securities are carried at fair value with unrealized gains and losses reported in equity as a component of accumulated other comprehensive income or loss. The fair value of the marketable securities is determined using Level 1 inputs under FASB Accounting Standards Codification (“ASC”) 820, “Fair Value Measurements and Disclosures.” Level 1 inputs represent quoted prices available in an active market for identical investments as of the reporting date. Gains and losses on securities sold are based on the specific identification method, and are reported as a component of interest, dividend and other investment income.
Restricted Cash	Restricted Cash. We classify all cash pledged as collateral to secure certain obligations and all cash whose use is limited as restricted cash. During 2015, pursuant to the terms of our $15.1 million 4.99% Note, due January 6, 2024 (See Note 6), which is collateralized by our Anthem Marketplace property, we were required by the lenders thereunder to establish a cash management account controlled by the lenders to collect all amounts generated by our Anthem Marketplace property in order to collateralize such promissory note. As a result, these amounts are reported in the consolidated statements of cash flows under cash flows from financing activities as change in restricted cash.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities. We utilize derivative financial instruments, principally interest rate swaps, to manage our exposure to fluctuations in interest rates. We have established policies and procedures for risk assessment, and the approval, reporting and monitoring of derivative financial instruments. We recognize our interest rate swaps as cash flow hedges with the effective portion of the changes in fair value recorded in comprehensive income (loss) and subsequently reclassified into earnings in the period that the hedged transaction affects earnings. Any ineffective portion of a cash flow hedges' change in fair value is recorded immediately into earnings. Our cash flow hedges are determined using Level 2 inputs under ASC 820. Level 2 inputs represent quoted prices in active markets for similar assets or liabilities; quoted prices in markets that are not active; and model-derived valuations whose inputs are observable. As of September 30, 2016, we consider our cash flow hedges to be highly effective.
Development Properties	Development Properties. Land, buildings and improvements are recorded at cost. Expenditures related to the development of real estate are carried at cost which includes capitalized carrying charges and development costs. Carrying charges (interest, real estate taxes, loan fees, and direct and indirect development costs related to buildings under construction), are capitalized as part of construction in progress. The capitalization of such costs ceases when the property, or any completed portion, becomes available for occupancy. For the three months ended September 30, 2016, approximately $103,000 and $16,000 in interest expense and real estate taxes, respectively, were capitalized, and for the nine months ended September 30, 2016, approximately $235,000 and $48,000 in interest expense and real estate taxes, respectively, were capitalized. For the three months ended September 30, 2015, approximately $25,000 and $16,000 in interest expense and real estate taxes, respectively, were capitalized, and for the nine months ended September 30, 2015, approximately $83,000 and $53,000 in interest expense and real estate taxes, respectively, were capitalized.
Real Estate Held for Sale and Discontinued Operations	Real Estate Held for Sale and Discontinued Operations. We consider a commercial property to be held for sale when it meets all of the criteria established under ASC 205, “Presentation of Financial Statements.” For commercial properties classified as held for sale, assets and liabilities are presented separately for all periods presented. In accordance with ASC 205, a discontinued operation may include a component of an entity or a group of components of an entity. A disposal of a component of an entity or a group of components of an entity is reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity's operations and financial results when the component of an entity or group of components of an entity is classified as held for sale, disposed of by sale or disposed of other than by sale, respectively. In addition, ASC 205 requires us to provide additional disclosures about both discontinued operations and the disposal of an individually significant component of an entity that does not meet the criteria for a discontinued operation.
Share-Based Compensation	Share-Based Compensation. From time to time, we award nonvested restricted common share awards or restricted common share unit awards, which may be converted into common shares, to executive officers and employees under our 2008 Long-Term Equity Incentive Ownership Plan (the “2008 Plan”). The vast majority of the awarded shares and units vest when certain performance conditions are met. We recognize compensation expense when achievement of the performance conditions is probable based on management's most recent estimates using the fair value of the shares as of the grant date. We recognized $3,042,000 and $1,859,000 in share-based compensation for the three months ended September 30, 2016 and 2015, respectively, and we recognized $6,886,000 and $5,202,000 in share-based compensation for the nine months ended September 30, 2016 and 2015, respectively.
Noncontrolling Interests	Noncontrolling Interests. Noncontrolling interests is the portion of equity in a subsidiary not attributable to a parent. The ownership interests not held by the parent are considered noncontrolling interests. Accordingly, we have reported noncontrolling interests in equity on the consolidated balance sheets but separate from Whitestone's equity. On the consolidated statements of operations, subsidiaries are reported at the consolidated amount, including both the amount attributable to Whitestone and noncontrolling interests. The consolidated statement of changes in equity is included for quarterly financial statements, including beginning balances, activity for the period and ending balances for shareholders' equity, noncontrolling interests and total equity.
Recent Accounting Pronouncements	Recent Accounting Pronouncements. In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts. In August 2015, the FASB issued guidance to clarify that debt issuance costs related to line-of-credit agreements may still be presented as an asset and subsequently amortized ratably over the term of such arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit. This guidance was effective for reporting periods beginning on or after December 15, 2015 and is to be applied retrospectively. We have adopted this guidance for all periods presented. In February 2016, the FASB issued guidance requiring lessees to recognize a lease liability and a right-of-use asset for all leases. Lessor accounting will remain largely unchanged. The guidance will also require new qualitative and quantitative disclosures to help financial statement users better understand the timing, amount and uncertainty of cash flows arising from leases. This guidance will be effective for reporting periods beginning on or after December 15, 2018, with early adoption permitted. We are currently evaluating the impact of this guidance and its impact on our consolidated financial statements. In March 2016, the FASB issued guidance simplifying the accounting for share-based payment transactions, including the income tax consequences, balance sheet classification of awards and the classification on the statement of cash flows. This guidance will be effective for reporting periods beginning on or after December 15, 2016, and interim periods within those fiscal years. We are currently evaluating the impact of this guidance and its impact on our consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2016

Basis of Consolidation. We are the sole general partner of the Operating Partnership and possess full legal control and authority over the operations of the Operating Partnership. As of September 30, 2016 and December 31, 2015, we owned a majority of the partnership interests in the Operating Partnership. Consequently, the accompanying consolidated financial statements include the accounts of the Operating Partnership. All significant inter-company balances have been eliminated. Noncontrolling interests in the accompanying consolidated financial statements represents the share of equity and earnings of the Operating Partnership allocable to holders of partnership interests other than us. Net income or loss is allocated to noncontrolling interests based on the weighted average percentage ownership of the Operating Partnership during the period. Issuance of additional common shares of beneficial interest in Whitestone (the “common shares”) and units of limited partnership interest in the Operating Partnership that are convertible into cash or, at our option, common shares on a one-for-one basis (the “OP units”) changes the ownership interests of both the noncontrolling interests and Whitestone.

Basis of Accounting

Basis of Accounting. Our financial records are maintained on the accrual basis of accounting whereby revenues are recognized when earned and expenses are recorded when incurred.

Use of Estimates

Use of Estimates. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates that we use include the estimated fair values of properties acquired, the estimated useful lives for depreciable and amortizable assets and costs, the estimated allowance for doubtful accounts, the estimated fair value of interest rate swaps and the estimates supporting our impairment analysis for the carrying values of our real estate assets. Actual results could differ from those estimates.

Reclassifications

Reclassifications. We have reclassified certain prior period amounts in the accompanying consolidated financial statements in order to be consistent with the current period presentation. During the nine months ended September 30, 2016, we reclassified certain deferred financing costs, previously classified as an asset as a direct reduction from the carrying amount of certain debt liabilities for all periods presented. Deferred financing costs related to our unsecured line of credit have not been reclassified. See Note 6 for additional information. These reclassifications had no effect on net income or equity.

Marketable Securities

Marketable Securities. We classify our existing marketable equity securities as available-for-sale in accordance with the Financial Accounting Standards Board's (“FASB”) Investments-Debt and Equity Securities guidance. These securities are carried at fair value with unrealized gains and losses reported in equity as a component of accumulated other comprehensive income or loss. The fair value of the marketable securities is determined using Level 1 inputs under FASB Accounting Standards Codification (“ASC”) 820, “Fair Value Measurements and Disclosures.” Level 1 inputs represent quoted prices available in an active market for identical investments as of the reporting date. Gains and losses on securities sold are based on the specific identification method, and are reported as a component of interest, dividend and other investment income.

Restricted Cash

Restricted Cash. We classify all cash pledged as collateral to secure certain obligations and all cash whose use is limited as restricted cash. During 2015, pursuant to the terms of our $15.1 million 4.99% Note, due January 6, 2024 (See Note 6), which is collateralized by our Anthem Marketplace property, we were required by the lenders thereunder to establish a cash management account controlled by the lenders to collect all amounts generated by our Anthem Marketplace property in order to collateralize such promissory note. As a result, these amounts are reported in the consolidated statements of cash flows under cash flows from financing activities as change in restricted cash.

Derivative Instruments and Hedging Activities

Derivative Instruments and Hedging Activities. We utilize derivative financial instruments, principally interest rate swaps, to manage our exposure to fluctuations in interest rates. We have established policies and procedures for risk assessment, and the approval, reporting and monitoring of derivative financial instruments. We recognize our interest rate swaps as cash flow hedges with the effective portion of the changes in fair value recorded in comprehensive income (loss) and subsequently reclassified into earnings in the period that the hedged transaction affects earnings. Any ineffective portion of a cash flow hedges' change in fair value is recorded immediately into earnings. Our cash flow hedges are determined using Level 2 inputs under ASC 820. Level 2 inputs represent quoted prices in active markets for similar assets or liabilities; quoted prices in markets that are not active; and model-derived valuations whose inputs are observable. As of September 30, 2016, we consider our cash flow hedges to be highly effective.

Development Properties

Development Properties. Land, buildings and improvements are recorded at cost. Expenditures related to the development of real estate are carried at cost which includes capitalized carrying charges and development costs. Carrying charges (interest, real estate taxes, loan fees, and direct and indirect development costs related to buildings under construction), are capitalized as part of construction in progress. The capitalization of such costs ceases when the property, or any completed portion, becomes available for occupancy. For the three months ended September 30, 2016, approximately $103,000 and $16,000 in interest expense and real estate taxes, respectively, were capitalized, and for the nine months ended September 30, 2016, approximately $235,000 and $48,000 in interest expense and real estate taxes, respectively, were capitalized. For the three months ended September 30, 2015, approximately $25,000 and $16,000 in interest expense and real estate taxes, respectively, were capitalized, and for the nine months ended September 30, 2015, approximately $83,000 and $53,000 in interest expense and real estate taxes, respectively, were capitalized.

Real Estate Held for Sale and Discontinued Operations

Real Estate Held for Sale and Discontinued Operations. We consider a commercial property to be held for sale when it meets all of the criteria established under ASC 205, “Presentation of Financial Statements.” For commercial properties classified as held for sale, assets and liabilities are presented separately for all periods presented.

In accordance with ASC 205, a discontinued operation may include a component of an entity or a group of components of an entity. A disposal of a component of an entity or a group of components of an entity is reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity's operations and financial results when the component of an entity or group of components of an entity is classified as held for sale, disposed of by sale or disposed of other than by sale, respectively. In addition, ASC 205 requires us to provide additional disclosures about both discontinued operations and the disposal of an individually significant component of an entity that does not meet the criteria for a discontinued operation.

Share-Based Compensation

Share-Based Compensation. From time to time, we award nonvested restricted common share awards or restricted common share unit awards, which may be converted into common shares, to executive officers and employees under our 2008 Long-Term Equity Incentive Ownership Plan (the “2008 Plan”). The vast majority of the awarded shares and units vest when certain performance conditions are met. We recognize compensation expense when achievement of the performance conditions is probable based on management's most recent estimates using the fair value of the shares as of the grant date. We recognized $3,042,000 and $1,859,000 in share-based compensation for the three months ended September 30, 2016 and 2015, respectively, and we recognized $6,886,000 and $5,202,000 in share-based compensation for the nine months ended September 30, 2016 and 2015, respectively.

Noncontrolling Interests

Noncontrolling Interests. Noncontrolling interests is the portion of equity in a subsidiary not attributable to a parent. The ownership interests not held by the parent are considered noncontrolling interests. Accordingly, we have reported noncontrolling interests in equity on the consolidated balance sheets but separate from Whitestone's equity. On the consolidated statements of operations, subsidiaries are reported at the consolidated amount, including both the amount attributable to Whitestone and noncontrolling interests. The consolidated statement of changes in equity is included for quarterly financial statements, including beginning balances, activity for the period and ending balances for shareholders' equity, noncontrolling interests and total equity.

Recent Accounting Pronouncements

Recent Accounting Pronouncements. In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts. In August 2015, the FASB issued guidance to clarify that debt issuance costs related to line-of-credit agreements may still be presented as an asset and subsequently amortized ratably over the term of such arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit. This guidance was effective for reporting periods beginning on or after December 15, 2015 and is to be applied retrospectively. We have adopted this guidance for all periods presented.

In February 2016, the FASB issued guidance requiring lessees to recognize a lease liability and a right-of-use asset for all leases. Lessor accounting will remain largely unchanged. The guidance will also require new qualitative and quantitative disclosures to help financial statement users better understand the timing, amount and uncertainty of cash flows arising from leases. This guidance will be effective for reporting periods beginning on or after December 15, 2018, with early adoption permitted. We are currently evaluating the impact of this guidance and its impact on our consolidated financial statements.

In March 2016, the FASB issued guidance simplifying the accounting for share-based payment transactions, including the income tax consequences, balance sheet classification of awards and the classification on the statement of cash flows. This guidance will be effective for reporting periods beginning on or after December 15, 2016, and interim periods within those fiscal years. We are currently evaluating the impact of this guidance and its impact on our consolidated financial statements.