Acquisitions	6 Months Ended
Acquisitions	Jun. 30, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions Lansing Building Products, LLC In April 2020, the Company acquired a controlling interest in Lansing Building Products, LLC, a supplier of exterior building products and materials to professional contractors throughout the U.S., which simultaneously acquired the distribution business of Harvey Building Products to enhance geographic reach and scale (together, Lansing), bringing the Company's ownership in Lansing to 91%. Under the terms of the acquisition agreement, the Company has the option to acquire the remaining equity interests and the remaining equity interests have the option to sell their interests to the Company in the future. The redemption value of the remaining equity interests is generally based on Lansing's earnings in specified periods preceding the redemption dates. Total consideration for both transactions was $556.2 million, all of which was cash. The purchase price was preliminarily allocated to the acquired assets and liabilities of Lansing based on estimated fair value at the acquisition date. The Company preliminarily recognized goodwill of $295.6 million, which is primarily attributable to expected future earnings and cash flow potential of Lansing. The majority of the goodwill recognized is not expected to be deductible for income tax purposes. The Company also preliminarily recognized other intangible assets of $211.0 million, which includes $189.0 million of customer relationships and $22.0 million of trade names, which are expected to be amortized over a weighted average period of 16 years and 14 years, respectively. The Company also recognized redeemable noncontrolling interests of $43.6 million. Results attributable to Lansing are included in the Company's Markel Ventures segment. The Company has not completed the process of determining the fair value of the assets acquired and liabilities assumed. These valuations are required to be completed within 12 months from the acquisition date. As a result, the fair value recorded for these items is a provisional estimate and may be subject to adjustment. Once completed, any adjustments resulting from the valuations may impact the individual amounts recorded for assets acquired and liabilities assumed, as well as the residual goodwill. VSC Fire & Security, Inc. In November 2019, the Company acquired VSC Fire & Security, Inc. (VSC), a provider of comprehensive fire protection, life safety, and low voltage solutions to retailers, commercial campuses, healthcare facilities, and government properties throughout the southeastern United States. Total consideration for the acquisition was $225.0 million, which included cash of $204.0 million. Total consideration also included the estimated fair value of contingent consideration the Company expects to pay in 2021 based on VSC’s earnings, as defined in the purchase agreement. As of December 31, 2019, the purchase price was preliminarily allocated to the acquired assets and liabilities of VSC based on estimated fair value at the acquisition date. During the first quarter of 2020, the Company completed the process of determining the fair value of the assets and liabilities acquired with VSC. The Company recognized goodwill of $124.9 million, which is primarily attributable to expected future earnings and cash flow potential of VSC. All of the goodwill recognized is deductible for income tax purposes. The Company also recognized other intangible assets of $64.5 million, which includes $48.0 million of customer relationships, $14.0 million of trade names and $2.5 million of other intangible assets, which are being amortized over a weighted average period of 12 years, 12 years and 8 years, respectively. Results attributable to VSC are included in the Company's Markel Ventures segment.