Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2017
Summary of Significant Accounting Policies [Abstract]
Description of Business	Description of Business: Baldwin & Lyons, Inc. (the "Company"), based in Carmel, Indiana, is a specialty property-casualty insurer providing liability coverage for large to small-sized trucking and public transportation fleets. The Company operates as one reportable property and casualty insurance segment, offering a range of products and services, the most significant being commercial automobile and workers' compensation insurance products. The Company determined that its business constituted one reportable property and casualty insurance segment as of January 1, 2017. During 2016 and prior years, the Company had two reportable segments – property and casualty insurance and reinsurance. The Company moved to a single reportable segment based on how its operating results are regularly reviewed by the Company's chief operating decision maker to make decisions about resources to be allocated to the segment and to assess its performance. The prior period segment information throughout this Quarterly Report on Form 10-Q was updated to conform to the current year presentation.
Basis of Presentation	Basis of Presentation: The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and do not include all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for fair presentation have been included. Interim financial statements should be read in conjunction with the Company's annual audited financial statements and other disclosures included in the Company's most recent Annual Report on Form 10-K. Operating results for interim periods are not necessarily indicative of results that may be expected for the year ended December 31, 2017. Investments: Carrying amounts for fixed maturity securities represent fair value and are based on quoted market prices, where available, or broker/dealer quotes for specific securities where quoted market prices are not available. Equity securities are carried at quoted market prices (fair value). The Company accounts for investments in limited partnerships using the equity method of accounting, which requires an investor in a limited partnership to record its proportionate share of the limited partnership's net income. To the extent that the limited partnership investees include both realized and unrealized investment gains or losses in the determination of net income or loss, then the Company would also recognize, through its condensed consolidated statements of income, its proportionate share of the investee's unrealized, as well as realized, investment gains or losses.
Investments	Short-term and other investments are carried at cost, which approximates their fair values. Realized gains and losses on disposals of investments are recorded on the trade date and are determined by specific identification of cost of investments sold and are included in income. All fixed maturity and equity securities are considered to be available for sale; the related unrealized net gains or losses (net of applicable tax effect) are reflected directly in shareholders' equity. Included within available for sale fixed maturity securities are convertible debt securities. The changes in fair values of insurance-linked securities and portions of the changes in fair values of convertible debt securities are reflected as a component of net realized gains (losses) on investments. In accordance with the Financial Accounting Standards Board's ("FASB") other-than-temporary impairment guidance, if a fixed maturity security is in an unrealized loss position and the Company has the intent to sell the fixed maturity security, or it is more likely than not that the Company will have to sell the fixed maturity security before recovery of its amortized cost basis, the decline in value is deemed to be other-than-temporary and is recorded to net realized losses on investments in the condensed consolidated statements of operations. For impaired fixed maturity securities that the Company does not intend to sell or in cases where it is more likely than not that the Company will not have to sell such securities, but the Company expects that it will not fully recover the amortized cost basis, the credit component of the other-than-temporary impairment is recognized in net realized losses on investments in the condensed consolidated statements of operations and the non-credit component of the other-than-temporary impairment is recognized directly in shareholders' equity (accumulated other comprehensive income). The credit component of an other-than-temporary impairment is determined by comparing the net present value of projected future cash flows with the amortized cost basis of the fixed maturity security. The net present value is calculated by discounting the Company's best estimate of projected future cash flows at the appropriate effective interest rate. The unrealized net gains or losses (net of applicable tax effect) related to equity securities are reflected directly in shareholders' equity, unless a decline in value is determined to be other-than-temporary, in which case the loss is charged to income. In determining if and when a decline in market value below cost is other-than-temporary, an objective analysis is made of each individual security where current market value is less than cost. For any equity security where the unrealized loss exceeds a set percentage of original or adjusted cost, and where that decline has existed for a set period of time, the decline is treated as an other-than-temporary impairment. For any equity security where the decline has existed for a period of at least one year, the decline is treated as an other-than-temporary impairment. Additionally, the Company takes into account any known subjective information in evaluating for impairment, without consideration of the Company's quantitative criteria defined above, as well as the Company's intent and ability to retain the equity security for a period of time sufficient to allow for such recovery in fair value.
Recent Accounting Pronouncements	Recent Accounting Pronouncements: In January 2016, the FASB issued Accounting Standards Update “ASU” 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, or ASU 2016-01. The amendments in ASU 2016-01 change the accounting for non-consolidated equity investments that are not accounted for under the equity method of accounting by requiring changes in fair value to be recognized in income. Under current guidance, changes in fair value for investments of this nature are recognized in accumulated other comprehensive income as a component of shareholders’ equity. Additionally, ASU 2016-01 simplifies the impairment assessment of equity investments without readily determinable fair values; requires entities to use the exit price when estimating the fair value of financial instruments; and modifies various presentation disclosure requirements for financial instruments. ASU 2016-01 is effective for interim and annual reporting periods beginning after December 15, 2017. The Company has not yet evaluated the impact of this guidance. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), as amended by subsequently issued ASUs, to clarify the principles for recognizing revenue. While insurance contracts are not within the scope of this updated guidance, the Company's service and fee income could be subject to this updated guidance. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. The following steps are applied in the updated guidance: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of ASU 2014-09 to the quarter ending March 31, 2018. The Company has performed an initial evaluation of the impact this guidance will have on its results of operations, financial position or liquidity. The Company does not expect the guidance to have a material impact on its results of operations, financial position or liquidity. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), or ASU 2016-02. Upon the effective date, ASU 2016-02 will supersede the current lease guidance in ASC Topic 840, Leases. Under the new guidance, lessees will be required to recognize for all leases, with the exception of short-term leases, a lease liability, which is a lessee's obligation to make lease payments arising from a lease, measured on a discounted basis. Concurrently, lessees will be required to recognize a right-of-use asset, which is an asset that represents the lessee's right to use, or control the use of, a specified asset for the lease term. ASU 2016-02 is effective for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The guidance is required to be applied using a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative periods presented in the financial statements. The Company is currently evaluating the effects that adoption of ASU 2016-02 will have on its consolidated financial statements, results of operations and cash flows. The Company does not expect the guidance to have a material impact on its results of operations, financial position or liquidity. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, or ASU 2016-13. This update introduces a current expected credit loss model for measuring expected credit losses for certain types of financial instruments held at the reporting date based on historical experience, current conditions and reasonable supportable forecasts. ASU 2016-13 replaces the current incurred loss model for measuring expected credit losses, requires expected losses on available-for-sale debt securities to be recognized through an allowance for credit losses rather than as reductions in the amortized cost of the securities, and provides for additional disclosure requirements. ASU 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019, with early adoption permitted for interim and annual reporting periods beginning after December 15, 2018. The Company is currently evaluating the effects that adoption of ASU 2016-13 will have on its consolidated financial statements, results of operations and cash flows. In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, or ASU 2017-04. This amendment removes Step 2 of the goodwill impairment test under current guidance, which requires a hypothetical purchase price allocation. The new guidance requires an impairment charge to be recognized for the amount by which the carrying amount exceeds the reporting unit's fair value. ASU 2017-04 is effective for interim and annual reporting periods beginning after December 15, 2020, with early adoption permitted. The Company does not expect the guidance to have a material impact on its results of operations, financial position or liquidity.

Disclosure of accounting policy for investments in financial assets, including marketable securities (debt and equity securities with readily determinable fair values), investments accounted for under the equity method and cost method, securities borrowed and loaned, and repurchase and resale agreements. For marketable securities, the disclosure may include the entity's accounting treatment for transfers between investment categories and how the fair values for such securities are determined. Also, for all investments, an entity may describe its policy for assessing, recognizing and measuring impairment of the investment.