Basis of Presentation	3 Months Ended
Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements and notes thereto contain all adjustments, consisting only of normal recurring adjustments, necessary to present fairly, in accordance with accounting principles generally accepted in the United States of America (“GAAP”), the financial position of MidSouth Bancorp, Inc. (the “Company”) and its subsidiaries as of March 31, 2016 and the results of their operations and their cash flows for the periods presented. The interim financial information should be read in conjunction with the annual consolidated financial statements and the notes thereto included in the Company’s 2015 Annual Report on Form 10-K. The results of operations for the three-month period ended March 31, 2016 are not necessarily indicative of the results to be expected for the entire year. 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 consolidated financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. Summary of Significant Accounting Policies — The accounting and reporting policies of the Company conform with GAAP and general practices within the banking industry. There have been no material changes or developments in the application of accounting principles or in our evaluation of the accounting estimates and the underlying assumptions or methodologies that we believe to be Critical Accounting Policies and Estimates as disclosed in our 2015 Annual Report on Form 10-K. Recent Accounting Pronouncements — ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities is the first ASU issued under the FASB's financial instruments project. ASU 2016-01 primarily affects the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. The guidance in this ASU requires all equity securities with readily determinable fair values to be measured at fair value on the balance sheet, with changes in fair value recorded through earnings. For financial liabilities that are measured at fair value in accordance with the fair value option, the guidance requires changes in the fair value of a financial liabilities attributable to a change in instrument-specific credit risk to be recorded separately in other comprehensive income. This ASU eliminates the requirement to disclose the methods and significant assumptions used to estimate fair value. It does require public entities to use the exit price when measuring the fair value of financial instruments measured at amortized cost for disclosure purposes In addition, the new guidance requires financial assets and financial liabilities to be presented separately in the notes to the financial statements, grouped by measurement category and form of financial asset. The effective date of this Update is for fiscal years beginning on or after December 15, 2017. The Company is evaluating the impact, if any, that ASU 2016-01 will have on its financial position, results of operations, and its financial statement disclosures. ASU 2016-02, Leases (Topic 842) was issued with the intention of improving financial reporting about leasing transactions. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, unlike current GAAP - which requires only capital leases to be recognized on the balance sheet - the guidance in the ASU will require both types of leases to be recognized on the balance sheet. The ASU also will require disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. The effective date of this Update is for fiscal years beginning on or after December 15, 2018. The Company is evaluating the impact that ASU 2016-02 will have on its financial position, results of operations, and its financial statement disclosures. ASU 2016-09, Compensation - Stock Compensation (Topic 718) was issued as part of the FASB's simplification initiative. Under the new guidance, several aspects of the accounting for share-based payment award transactions are simplified, including: (a) income tax consequences; (b) classification of awards as either equity or liabilities; and (c) classification on the statement of cash flows. The effective date of this Update is for fiscal years beginning on or after December 15, 2016. The Company is evaluating the impact that ASU 2016-09 will have on its financial position, results of operations, and its financial statement disclosures.

Basis of Presentation

The accompanying unaudited consolidated financial statements and notes thereto contain all adjustments, consisting only of normal recurring adjustments, necessary to present fairly, in accordance with accounting principles generally accepted in the United States of America (“GAAP”), the financial position of MidSouth Bancorp, Inc. (the “Company”) and its subsidiaries as of March 31, 2016 and the results of their operations and their cash flows for the periods presented. The interim financial information should be read in conjunction with the annual consolidated financial statements and the notes thereto included in the Company’s 2015 Annual Report on Form 10-K.

The results of operations for the three-month period ended March 31, 2016 are not necessarily indicative of the results to be expected for the entire year.

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 consolidated financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates.

Summary of Significant Accounting Policies — The accounting and reporting policies of the Company conform with GAAP and general practices within the banking industry. There have been no material changes or developments in the application of accounting principles or in our evaluation of the accounting estimates and the underlying assumptions or methodologies that we believe to be Critical Accounting Policies and Estimates as disclosed in our 2015 Annual Report on Form 10-K.

Recent Accounting Pronouncements — ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities is the first ASU issued under the FASB's financial instruments project. ASU 2016-01 primarily affects the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. The guidance in this ASU requires all equity securities with readily determinable fair values to be measured at fair value on the balance sheet, with changes in fair value recorded through earnings. For financial liabilities that are measured at fair value in accordance with the fair value option, the guidance requires changes in the fair value of a financial liabilities attributable to a change in instrument-specific credit risk to be recorded separately in other comprehensive income. This ASU eliminates the requirement to disclose the methods and significant assumptions used to estimate fair value. It does require public entities to use the exit price when measuring the fair value of financial instruments measured at amortized cost for disclosure purposes In addition, the new guidance requires financial assets and financial liabilities to be presented separately in the notes to the financial statements, grouped by measurement category and form of financial asset. The effective date of this Update is for fiscal years beginning on or after December 15, 2017. The Company is evaluating the impact, if any, that ASU 2016-01 will have on its financial position, results of operations, and its financial statement disclosures.

ASU 2016-02, Leases (Topic 842) was issued with the intention of improving financial reporting about leasing transactions. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, unlike current GAAP - which requires only capital leases to be recognized on the balance sheet - the guidance in the ASU will require both types of leases to be recognized on the balance sheet. The ASU also will require disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. These disclosures include qualitative and quantitative requirements, providing additional information about the amounts recorded in the financial statements. The effective date of this Update is for fiscal years beginning on or after December 15, 2018. The Company is evaluating the impact that ASU 2016-02 will have on its financial position, results of operations, and its financial statement disclosures.

ASU 2016-09, Compensation - Stock Compensation (Topic 718) was issued as part of the FASB's simplification initiative. Under the new guidance, several aspects of the accounting for share-based payment award transactions are simplified, including: (a) income tax consequences; (b) classification of awards as either equity or liabilities; and (c) classification on the statement of cash flows. The effective date of this Update is for fiscal years beginning on or after December 15, 2016. The Company is evaluating the impact that ASU 2016-09 will have on its financial position, results of operations, and its financial statement disclosures.