Summary of Significant Accounting Policies | Summary of Significant Accounting Policies The summary of significant accounting policies presented below is designed to assist in understanding the Company’s condensed consolidated financial statements. Such condensed consolidated financial statements and the accompanying notes thereto are the representation of management. The accompanying condensed consolidated unaudited financial statements of the Company have been prepared in accordance with the accounting principles generally accepted in the United States, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting of normal and recurring nature considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2017 are not necessarily indicative of the results that may be expected for the year ended December 31, 2017 . The condensed consolidated balance sheet at December 31, 2016 has been derived from the audited consolidated financial statements at that date but does not include all of the information and notes required by GAAP for complete financial statements. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s audited consolidated financial statements as of and for the year ended December 31, 2016 and related notes thereto set forth in the Company’s Annual Report on Form 10-K, filed with the SEC on March 30, 2017. Principles of Consolidation and Basis of Presentation The accompanying condensed consolidated financial statements include the accounts of the Company, the Operating Partnership, all majority-owned subsidiaries and controlled subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP necessarily 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 condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates are made and evaluated on an ongoing basis using information that is currently available as well as various other assumptions believed to be reasonable under the circumstances. Actual results could differ from those estimates. Allowance for Uncollectible Accounts Tenant receivables and unbilled deferred rent receivables are carried net of the allowances for uncollectible amounts. An allowance will be maintained for estimated losses resulting from the inability of certain tenants to meet the contractual obligations under their lease agreements. The Company also maintains an allowance for deferred rent receivables arising from the straight-lining of rents. The Company’s determination of the adequacy of these allowances is based primarily upon evaluations of historical loss experience, the tenant’s financial condition, security deposits, letters of credit, lease guarantees and current economic conditions and other relevant factors. For the three months ended March 31, 2017, the Company recorded $7,664,000 in provision for doubtful accounts related to reserves for rental and parking revenue and tenant reimbursement revenue, which are recognized in the accompanying condensed consolidated statements of comprehensive income as a deduction from rental and parking revenue and tenant reimbursement revenue. The provision for doubtful accounts is the result of two tenants experiencing financial difficulties, which the Company believes will result in material new lease terms. Notes Receivable Notes receivable are reported at their outstanding principal balance, net of any unearned income, unamortized deferred fees and costs and allowances for doubtful accounts. The unamortized deferred fees and costs are amortized over the life of the notes receivable, as applicable, and recorded in other interest and dividend income in the accompanying condensed consolidated statements of comprehensive income . The Company evaluates the collectability of both interest and principal on each note receivable to determine whether it is collectible primarily through the evaluation of credit quality indicators, such as the tenant's financial condition, evaluations of historical loss experience, current economic conditions and other relevant factors. Impairment occurs when it is determined probable that the Company will not be able to collect principal and interest amounts due according to the contractual terms of the note. Evaluating a note receivable for potential impairment requires management to exercise significant judgment. As of March 31, 2017 and December 31, 2016 , the aggregate balance on the Company's notes receivable before allowances for loan losses was $20,275,000 and $19,422,000 , respectively. For the three months ended March 31, 2017 the Company recorded $2,484,000 as an allowance to reduce the carrying value of two notes receivable and accrued interest in provision for loan losses in the accompanying condensed consolidated financial statements. Concentration of Credit Risk and Significant Leases As of March 31, 2017 , the Company had cash on deposit, including restricted cash, in certain financial institutions that had deposits in excess of current federally insured levels; however, the Company has not experienced any losses in such accounts. The Company limits its cash investments to financial institutions with high credit standings; therefore, the Company believes it is not exposed to any significant credit risk on its cash deposits. To date, the Company has experienced no loss of or lack of access to cash in its accounts. As of March 31, 2017 , the Company owned real estate investments in 46 MSAs, (including one real estate investment owned through a consolidated partnership), two of which accounted for 10.0% or more of contractual rental revenue. Real estate investments located in the Dallas-Ft. Worth-Arlington, Texas MSA and the Chicago-Naperville-Elgin, Illinois-Indiana-Wisconsin MSA accounted for an aggregate of 12.2% and 11.8% , respectively, of contractual rental revenue for the three months ended March 31, 2017 . As of March 31, 2017 , the Company had one exposure to tenant concentration that accounted for 10.0% or more of rental revenue. The leases with AT&T Services, Inc. accounted for 11.7% of rental revenue for the three months ended March 31, 2017 . Share Repurchase Program The Company’s share repurchase program allows for repurchases of shares of the Company’s common stock when certain criteria are met. The share repurchase program provides that all repurchases during any calendar year, including those redeemable upon death or a qualifying disability of a stockholder, are limited to those that can be funded with equivalent reinvestments pursuant to the DRIP Offerings during the prior calendar year and other operating funds, if any, as the board of directors, in its sole discretion, may reserve for this purpose. Repurchases of shares of the Company’s common stock are at the sole discretion of the Company’s board of directors. In addition, the Company’s board of directors, in its sole discretion, may amend, suspend, reduce, terminate or otherwise change the share repurchase program upon 30 days ' prior notice to the Company’s stockholders for any reason it deems appropriate. The share repurchase program provides that the Company will limit the number of shares repurchased during any calendar year to 5.0% of the number of shares of common stock outstanding as of December 31st of the previous calendar year. During the three months ended March 31, 2017 , the Company received valid repurchase requests related to approximately 1,232,000 shares of common stock, all of which were repurchased in full for an aggregate purchase price of approximately $12,101,000 (an average of $9.82 per share). During the three months ended March 31, 2016 , the Company received valid repurchase requests related to approximately 871,000 shares of common stock, all of which were repurchased in full for an aggregate purchase price of approximately $8,393,000 (an average of $9.64 per share). Earnings Per Share Basic earnings per share for all periods presented are computed by dividing net income attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. Shares of non-vested restricted common stock give rise to potentially dilutive shares of common stock. Diluted earnings per share are computed based on the weighted average number of shares outstanding and all potentially dilutive securities. For the three months ended March 31, 2017 and 2016 , diluted earnings per share reflected the effect of approximately 17,000 for each period of non-vested shares of restricted common stock that were outstanding as of such period. Recently Issued Accounting Pronouncements On May 28, 2014, the Financial Accounting Standards Board, or the FASB, issued ASU 2014-09, Revenue from Contracts with Customers , or ASU 2014-09. The objective of ASU 2014-09 is to clarify the principles for recognizing revenue and to develop a common revenue standard for GAAP. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods and 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. ASU 2014-09 defines a five-step process to achieve this core principle, which may require more judgment and estimates within the revenue recognition process than are required under existing GAAP. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606) Deferral of the Effective Date , or ASU 2015-14. ASU 2015-14 defers the effective date of ASU 2014-09 by one year to fiscal years and interim periods beginning after December 15, 2017. Early adoption is permitted as of the original effective date, which was annual reporting periods beginning after December 15, 2016, and the interim periods within that year. On March 17, 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers Principal versus Agent Considerations (Reporting Revenue Gross versus Net), or ASU 2016-08, which clarifies the implementation guidance on principal versus agent considerations in the new revenue recognition standard. ASU 2016-08 clarifies that an entity is a principal when it controls the specified good or service before that good or service is transferred to the customer, and is an agent when it does not control the specified good or service before it is transferred to the customer. The effective date and transition of this update is the same as the effective date and transition of ASU 2015-14. The Company believes the adoption of ASUs 2014-09 and 2016-08 will not have a material impact on the Company’s consolidated financial statements, but may result in additional disclosures. On February 25, 2016, the FASB issued ASU 2016-02 , Leases , or ASU 2016-02. ASU 2016-02 establishes the principles to increase the transparency about the assets and liabilities arising from leases. ASU 2016-02 results in a more faithful representation of the rights and obligations arising from leases by requiring lessees to recognize the lease assets and lease liabilities that arise from leases in the statement of financial position and to disclose qualitative and quantitative information about lease transactions and aligns lessor accounting and sale leaseback transactions guidance more closely to comparable guidance in Topic 606, Revenue from Contracts with Customers , and Topic 610, Other Income . ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company is in process of evaluating the impact ASU 2016-02 will have on the Company’s consolidated financial statements. On June 16, 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses, or ASU 2016-13. ASU 2016-13 requires more timely recording of credit losses on loans and other financial instruments that are not accounted for at fair value through net income, including loans held for investment, held-to-maturity debt securities, trade and other receivables, net investment in leases and other such commitments. ASU 2016-13 requires that financial assets measured at amortized cost be presented at the net amount expected to be collected, through an allowance for credit losses that is deducted from the amortized cost basis. The amendments in ASU 2016-13 require the Company to measure all expected credit losses based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the financial assets and eliminates the “incurred loss” methodology in current GAAP. ASU 2016-13 is effective for fiscal years, and interim periods within, beginning after December 15, 2019. Early adoption is permitted for fiscal years, and interim periods within, beginning after December 15, 2018. The Company is in the process of evaluating the impact ASU 2016-13 will have on the Company’s consolidated financial statements. On November 17, 2016, the FASB issued ASU 2016-18, Restricted Cash , or ASU 2016-18. ASU 2016-18 requires that a statement of cash flows explain the change during a reporting period in the total of cash, cash equivalents, and amounts generally described as restricted cash and restricted cash equivalents. This ASU states that transfers between cash, cash equivalents, and restricted cash are not part of the entity’s operating, investing, and financing activities. Therefore, restricted cash should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-18 is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. This ASU should be applied using a retrospective transition method to each period presented. The Company is in the process of evaluating the impact ASU 2016-18 will have on the Company’s consolidated statements of cash flows. On January 5, 2017, the Financial Accounting Standards Board, or the FASB, issued Accounting Standards Update, or ASU, 2017-01, Business Combinations , or ASU 2017-01. ASU 2017-01 clarifies the definition of a business. The objective of ASU 2017-01 is to add further guidance that assists entities in evaluating whether a transaction will be accounted for as an acquisition of an asset or a business. The guidance requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets. If so, the set of transferred asset and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs. The guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted using a prospective transition method. The Company adopted ASU 2017-01 effective October 1, 2016. On February 23, 2017, the FASB issued ASU 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets, or ASU 2017-05. ASU 2017-05 clarifies the scope of asset derecognition guidance and accounting for partial sales of nonfinancial assets. Partial sales of nonfinancial assets are common in the real estate industry and include transactions in which the seller retains an equity interest in the entity that owns the assets or has an equity interest in the buyer. ASU 2017-05 is effective for fiscal years beginning after December 15, 2017, including interim reporting periods within those fiscal years. Early adoption is permitted. The Company is in process of evaluating the impact ASU 2017-05 will have on the Company’s condensed consolidated financial statements. Reclassifications Certain prior period amounts have been reclassified to conform to the current financial statement presentation, with no effect on the Company’s condensed consolidated financial position or results of operations. |