Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The consolidated financial statements include the accounts of the Company and its consolidated partnerships and wholly-owned subsidiaries. Intercompany transactions and balances have been eliminated in consolidation. The Company presents its financial statements in accordance with accounting principles generally accepted in the United States (“GAAP”) as outlined in the Financial Accounting Standard Board’s Accounting Standards Codification (the “Codification” or “ASC”). The Codification is the single source of authoritative accounting principles applied by nongovernmental entities in the preparation of financial statements in conformity with GAAP. For the three years ended December 31, 2016, there were no items of other comprehensive income. Therefore, no presentation of comprehensive income is required. The Company evaluates all partnerships, joint ventures and other arrangements with variable interests to determine if the entity or arrangement qualifies as a variable interest entity (“VIE”), as defined in the Codification. If the entity or arrangement qualifies as a VIE and the Company is determined to be the primary beneficiary, the Company is required to consolidate the assets, liabilities, and results of operations of the VIE. At December 31, 2016, the Company had a joint venture with Callaway Gardens Resort, Inc. (“Callaway”) for the development of residential lots, which was funded fully through Company contributions. Callaway had the right to receive returns, but no obligation to fund any costs or absorb any losses. The Company was the sole decision maker for the venture and the development manager. The Company determined that the joint venture with Callaway was a VIE, and the Company was the primary beneficiary. Therefore, the Company consolidated this joint venture.
Recently Issued Accounting Standards	Recently Issued Accounting Standards: In 2015, the FASB issued ASC 2015-02 "Consolidation (Topic 810): Amendments to the Consolidation Analysis." All legal entities are subject to reevaluation under the revised consolidation model. The amendment modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities. It also eliminates the presumption that a general partner should consolidate a limited partnership. The guidance is effective for public entities with periods beginning after December 15, 2015 with early adoption permitted. The Company adopted this guidance effective January 1, 2016, and it did not have material impact on the consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, "Improvements to Employee Share-Based Payment Accounting." Under this ASU, the additional paid-in capital pool is eliminated, and an entity recognizes all excess tax benefits and tax deficiencies as income tax expense or benefit in the income statement. This ASU also eliminated the requirement to defer recognition of an excess tax benefit until all benefits are realized through a reduction to taxes payable. This ASU also changes the treatment of excess tax benefits as operating cash flows in the statement of cash flows. This ASU is effective for fiscal years beginning after December 15, 2016 with early adoption permitted. The Company expects to adopt this guidance effective January 1, 2017, and is currently assessing the potential impact of adopting the new guidance. In February 2016, the Financial Accounting Standards Board issued ASU 2016-02, "Leases," which amends the existing standards for lease accounting by requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting and reporting. The new standard will require lessees to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months and classify such leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method (finance leases) or on a straight-line basis over the term of the lease (operating leases). Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. ASU 2016-02 supersedes previous leasing standards. The guidance is effective for the fiscal years beginning after December 15, 2018 with early adoption permitted. The Company expects to adopt this guidance effective January 1, 2019, and is currently assessing the potential impact of adopting the new guidance. The Company expects to adopt this guidance using the " modified retrospective" method effective January 1, 2019. In the first quarter of 2016, the Company adopted ASU 2015-03, "Simplifying the Presentation of Debt Costs" ("ASU 2015-03"). In accordance with ASU 2015-03, the Company began recording deferred financing costs related to its mortgage notes payable as a reduction in the carrying amount of its notes payable on the consolidated balance sheets. The Company reclassified $2.5 million in deferred financing costs from other assets to notes payable in its December 31, 2015 consolidated balance sheet to conform to the current period's presentation. Deferred financing costs related to the Company’s unsecured revolving credit facility continue to be included in other assets within the Company’s balance sheets in accordance with ASU 2015-15 "Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements." In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers." Under the new guidance, companies will recognize revenue when the seller satisfies a performance obligation, which would be when the buyer takes control of the good or service. This new guidance could result in different amounts of revenue being recognized and could result in revenue being recognized in different reporting periods than under the current guidance. The new guidance specifically excludes revenue associated with lease contracts. ASU 2015-14, "Revenue from Contracts with Customers," was subsequently issued modifying the effective date to periods beginning after December 15, 2017, with early adoption permitted for periods beginning after December 15, 2016. The standard allows for either "full retrospective" adoption, meaning the standard is applied to all of the periods presented, or "modified retrospective" adoption, meaning the standard is applied only to the most recent period presented in the financial statements. The Company is currently assessing this guidance for future implementation and potential impact of adoption. The Company expects to adopt this guidance using the "modified retrospective" method effective January 1, 2018. In August 2014, the FASB issued ASU 205-40, "Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern," which requires management of all entities to evaluate whether there are conditions and events that raise substantial doubt about the entity's ability to continue as a going concern within one year after the financial statements are issued. The Company adopted ASU 205-40 as of December 31, 2016. In January 2017, the FASB issued ASU 2017-01, "Clarifying the Definition of a Business," which provides a more narrow definition of a business to be used in determining the accounting treatment of an acquisition. As a result, many acquisitions that previously qualified as business combinations will be treated as asset acquisitions. For asset acquisitions, acquisition costs may be capitalized, and the purchase price may be allocated on a relative fair value basis. ASU 2017-01 is effective prospectively for the Company on January 1, 2018, with early adoption permitted. The Company expects that most of its future acquisitions will qualify as asset acquisitions. Certain prior year amounts have been reclassified to conform with current year presentation on the consolidated statements of operations and the consolidated statements of equity. Separation expenses on the consolidated statements of operations have been reclassified from general and administrative expenses to other expenses. On the consolidated statements of equity, all components of common stock issued pursuant to stock-based compensation are aggregated into one line item. These changes do not affect the previously reported total costs and expenses in the consolidated statements of operations or the total equity in the consolidated statements of equity for any period.
Cost Capitalization, Depreciation and Amortization	Cost Capitalization: Costs related to planning, developing, leasing, and constructing a property, including costs of development personnel working directly on projects under development, are capitalized. In addition, the Company capitalizes interest to qualifying assets under development based on average accumulated expenditures outstanding during the period. In capitalizing interest to qualifying assets, the Company first uses the interest incurred on specific project debt, if any, and next uses the Company’s weighted average interest rate for non-project specific debt. The Company also capitalizes interest to investments accounted for under the equity method when the investee has property under development with a carrying value in excess of the investee’s borrowings. To the extent debt exists within an unconsolidated joint venture during the construction period, the venture capitalizes interest on that venture-specific debt. The Company capitalizes interest, real estate taxes, and certain operating expenses on the unoccupied portion of recently completed development properties from the date a project is substantially complete to the earlier of (1) the date on which the project achieves 90% economic occupancy or (2) one year after it is substantially complete. The Company capitalizes direct leasing costs related to leases that are probable of being executed. These costs include commissions paid to outside brokers, legal costs incurred to negotiate and document a lease agreement, and internal costs that are based on time spent by leasing personnel on successful leases. The Company allocates these costs to individual tenant leases and amortizes them over the related lease term. Depreciation and Amortization: Real estate assets are stated at depreciated cost less impairment losses, if any. Buildings are depreciated over their estimated useful lives, which range generally from 24 to 42 years. The life of a particular building depends upon a number of factors including whether the building was developed or acquired and the condition of the building upon acquisition. Furniture, fixtures and equipment are depreciated over their estimated useful lives of three to five years. Tenant improvements, leasing costs and leasehold improvements are amortized over the term of the applicable leases or the estimated useful life of the assets, whichever is shorter. The Company accelerates the depreciation of tenant assets if it estimates that the lease term will end prior to the termination date. This acceleration may occur if a tenant files for bankruptcy, vacates its premises or defaults in another manner on its lease. Deferred expenses are amortized over the period of estimated benefit. The Company uses the straight-line method for all depreciation and amortization.
Impairment	Impairment: For real estate assets that are considered to be held for sale according to accounting guidance or those that are distributed to stockholders in a spin-off, the Company records impairment losses if the fair value of the asset or disposal group net of estimated selling costs is less than the carrying amount. For those long-lived assets that are held and used according to accounting guidance, management reviews each asset for the existence of any indicators of impairment. If indicators of impairment are present, the Company calculates the expected undiscounted future cash flows to be derived from such assets. If the undiscounted cash flows are less than the carrying amount of the asset, the Company reduces the asset to its fair value and records an impairment loss.
Acquisition of Real Estate Assets	Acquisition of Real Estate Assets: The Company records the acquired tangible and intangible assets and assumed liabilities of operating property acquisitions at fair value at the acquisition date. The acquired assets and assumed liabilities for an operating property acquisition generally include but are not limited to: land, buildings and improvements, and identified tangible and intangible assets and liabilities associated with in-place leases, including leasing costs, value of above-market and below-market tenant leases, value of above-market and below-market ground leases, acquired in-place lease values, and tenant relationships, if any. The fair value of land is derived from comparable sales of land within the same submarket and/or region. The fair value of buildings and improvements, tenant improvements, and leasing costs are based upon current market replacement costs and other relevant market rate information. The fair value of the above-market or below-market component of an acquired in-place lease is based upon the present value (calculated using a market discount rate) of the difference between (i) the contractual rents to be paid pursuant to the lease over its remaining term and (ii) management’s estimate of the rents that would be paid using fair market rental rates and rent escalations at the date of acquisition over the remaining term of the lease. The amounts recorded for above-market and below-market ground leases are included in intangible liabilities and intangible assets, respectively, and are amortized on a straight-line basis into rental property revenues over the remaining terms of the applicable leases. The fair value of acquired in-place leases is derived based on management’s assessment of lost revenue and costs incurred for the period required to lease the “assumed vacant” property to the occupancy level when purchased. The amount recorded for acquired in-place leases is included in intangible assets and amortized as an increase to depreciation and amortization expense over the remaining term of the applicable leases.
Discontinued Operations	Discontinued Operations: Beginning in the second quarter 2014, only assets held for sale or disposals representing strategic shifts in operations are reflected in discontinued operations. Prior to 2014, the Company classified the results of operations of all properties that were sold or otherwise qualified as held for sale as discontinued operations if the property's operations were expected to be eliminated from ongoing operations and the Company would not have any significant continuing involvement in the operations of the property after the sale. During 2015, there were no held for sale assets or disposals that represented a strategic shift in operations. During 2016, the Company spun-off the combined operations of the Company's and Parkway's Houston assets into a separate public company. The Company considered this disposition to be a strategic shift in operations and reclassified the historical operations of its Houston business into discontinued operations on the consolidated statements of operations. The Company ceases depreciation of a property when it is categorized as held for sale.
Investment in Joint Ventures	Investment in Joint Ventures For joint ventures that the Company does not control, but over which it exercises significant influence, the Company uses the equity method of accounting. The Company's judgment with regard to its level of influence or control of an entity involves consideration of various factors including the form of its ownership interest; its representation in the entity's governance; its ability to participate in policy-making decisions; and the rights of other investors to participate in the decision-making process, to replace the Company as manager, and/or to liquidate the venture. These ventures are recorded at cost and adjusted for equity in earnings (losses) and cash contributions and distributions. Any difference between the carrying amount of these investments on the Company’s balance sheet and the underlying equity in net assets on the joint venture’s balance sheet is adjusted as the related underlying assets are depreciated, amortized, or sold. The Company generally allocates income and loss from an unconsolidated joint venture based on the venture's distribution priorities, which may be different from its stated ownership percentage. The Company evaluates the recoverability of its investment in unconsolidated joint ventures in accordance with accounting standards for equity investments by first reviewing each investment for any indicators of impairment. If indicators are present, the Company estimates the fair value of the investment. If the carrying value of the investment is greater than the estimated fair value, management makes an assessment of whether the impairment is “temporary” or “other-than-temporary.” In making this assessment, management considers the following: (1) the length of time and the extent to which fair value has been less than cost, (2) the financial condition and near-term prospects of the entity, and (3) the Company’s intent and ability to retain its interest long enough for a recovery in market value. If management concludes that the impairment is "other than temporary," the Company reduces the investment to its estimated fair value.
Noncontrolling Interest	Noncontrolling Interest The Company consolidates CPLP and certain joint ventures in which it owns a controlling interest. In cases where the entity’s documents do not contain a required redemption clause, the Company records the partner’s share of the entity in the equity section of the balance sheets in nonredeemable noncontrolling interests. In cases where the entity’s documents contain a provision requiring the Company to purchase the partner’s share of the venture at a certain value upon demand or at a future date, the Company records the partner’s share of the entity in redeemable noncontrolling interests on the balance sheets. The outside partners' interests in CPLP are redeemable into shares of cash or common stock of the Company in the Company's sole discretion. Therefore, noncontrolling interests associated with CPLP are considered nonredeemable noncontrolling interests. The noncontrolling partners' share of all consolidated entities' income is reflected in net income attributable to noncontrolling interest on the statements of operations.
Revenue Recognition	Revenue Recognition Rental Property Revenues: The Company recognizes contractual revenues from leases on a straight-line basis over the term of the respective lease. Certain of these leases also provide for percentage rents based upon the level of sales achieved by the lessee. Percentage rents are recognized once the specified sales target is achieved. In addition, leases typically provide for reimbursement of the tenants' share of real estate taxes, insurance, and other operating expenses to the Company. Operating expense reimbursements are recognized as the related expenses are incurred. During 2016, 2015, and 2014, the Company recognized $90.2 million, $93.3 million, and $86.0 million, respectively, in revenues, including discontinued operations, from tenants related to operating expenses. The Company makes valuation adjustments to all tenant-related accounts receivable based upon its estimate of the likelihood of collectibility of amounts due from the tenant. The amount of any valuation adjustment is based on the tenant’s credit and business risk, history of payment, and other factors considered by management. Fee Income: The Company recognizes development, management and leasing fees when earned. The Company recognizes development and leasing fees received from unconsolidated joint ventures and related salaries and other direct costs incurred by the Company as income and expense based on the percentage of the joint venture which the Company does not own. Correspondingly, the Company adjusts the investment in unconsolidated joint ventures asset when fees are paid to the Company by a joint venture in which the Company has an ownership interest. See note 6 for more information related to fee income recognized from unconsolidated joint ventures. Gain on Sale of Investment Properties: The Company recognizes a gain on sale of investment property when the sale of a property is consummated, the buyer’s initial and continuing investment is adequate to demonstrate commitment to pay, any receivable obtained is not subject to future subordination, the usual risks and rewards of ownership are transferred, and the Company has no substantial continuing involvement with the property. If the Company has a commitment to the buyer and that commitment is a specific dollar amount, this commitment is accrued and the gain on sale that the Company recognizes is reduced. If the Company has a construction commitment to the buyer, management makes an estimate of this commitment, defers a portion of the profit from the sale, and recognizes the deferred profit as or when the commitment is fulfilled.
Receivables	The Company makes valuation adjustments to all tenant-related accounts receivable based upon its estimate of the likelihood of collectibility of amounts due from the tenant. The amount of any valuation adjustment is based on the tenant’s credit and business risk, history of payment, and other factors considered by management.
Income Taxes	Income Taxes Cousins has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”). To qualify as a REIT, Cousins must distribute annually at least 90% of its adjusted taxable income, as defined in the Code, to its stockholders and satisfy certain other organizational and operating requirements. It is management’s current intention to adhere to these requirements and maintain Cousins’ REIT status. As a REIT, Cousins generally will not be subject to federal income tax at the corporate level on the taxable income it distributes to its stockholders. If Cousins fails to qualify as a REIT in any taxable year, it will be subject to federal income taxes at regular corporate rates (including any applicable alternative minimum tax) and may not be able to qualify as a REIT for four subsequent taxable years. Cousins may be subject to certain state and local taxes on its income and property, and to federal income taxes on its undistributed taxable income. CTRS is a C-Corporation for federal income tax purposes and uses the liability method for accounting for income taxes. Tax return positions are recognized in the financial statements when they are “more-likely-than-not” to be sustained upon examination by the taxing authority. Deferred income tax assets and liabilities result from temporary differences. Temporary differences are differences between the tax bases of assets and liabilities and their reported amounts in the financial statements that will result in taxable or deductible amounts in future periods. A valuation allowance may be placed on deferred income tax assets, if it is determined that it is more likely than not that a deferred tax asset may not be realized.
Stock-Based Compensation	Stock-Based Compensation The Company has several types of stock-based compensation plans. These plans are described in note 13, as are the accounting policies by type of award. The Company recognizes compensation expense, net of forfeitures, arising from share-based payment arrangements granted to employees and directors in general and administrative expense in the statements of operations over the related awards’ vesting period, which may be accelerated under the Company’s retirement feature.
Earnings per Share (EPS)	Earnings per Share (“EPS”) Net income per share-basic is calculated as net income available to common stockholders divided by the weighted average number of common shares outstanding during the period, including nonvested restricted stock which has nonforfeitable dividend rights. Net income per share-diluted is calculated as net income available to common stockholders plus noncontrolling interests in CPLP divided by the diluted weighted average number of common shares outstanding during the period. Diluted weighted average number of common shares uses the same weighted average share number as in the basic calculation and adds the potential dilution that would occur if the outside units in CPLP were converted into the Company's common stock and stock options (or any other contracts to issue common stock) were exercised and resulted in additional common shares outstanding, calculated using the treasury stock method. The numerator is reduced for the effect of preferred dividends in both the basic and diluted net income per share calculations. Stock options are dilutive when the average market price of the Company’s stock during the period exceeds the option exercise price.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash Cash and cash equivalents include cash and highly-liquid money market instruments. Highly-liquid money market instruments include securities and repurchase agreements with original maturities of three months or less, money market mutual funds, and United States Treasury Bills with maturities of 30 days or less. Restricted cash primarily represents amounts restricted under debt agreements for future capital expenditures or for specific future operating costs.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Reportable Segments	The Company's segments are based on the method of internal reporting which classifies operations by property type and geographical area. The segments by property type are: Office, Mixed-Use, and Other. The segments by geographical region are: Atlanta, Austin, Charlotte, Orlando, Tampa, Phoenix, and Other. These reportable segments represent an aggregation of operating segments reported to the Chief Operating Decision Maker based on similar economic characteristics that include the type of product and the geographical location. Each segment includes both consolidated operations and the Company's share of joint venture operations. Company management evaluates the performance of its reportable segments in part based on net operating income (“NOI”). NOI represents rental property expenses less rental property operating expenses. NOI is not a measure of cash flows or operating results as measured by GAAP, is not indicative of cash available to fund cash needs and should not be considered an alternative to cash flows as a measure of liquidity. All companies may not calculate NOI in the same manner. The Company considers NOI to be an appropriate supplemental measure to net income as it helps both management and investors understand the core operations of the Company's operating assets. NOI excludes corporate general and administrative expenses, interest expense, depreciation and amortization, impairments, gains/loss on sales of real estate, and other non-operating items. Segment net income, amount of capital expenditures, and total assets are not presented in the following tables because management does not utilize these measures when analyzing its segments or when making resource allocation decisions.