General	12 Months Ended
Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General Arch Capital Group Ltd. (“ACGL”) is a Bermuda public limited liability company which provides insurance and reinsurance on a worldwide basis through its wholly owned subsidiaries. ACGL was formed in September 2000 and became the sole shareholder of Arch Capital Group (U.S.) Inc. (“Arch-U.S.”) pursuant to an internal reorganization transaction completed in November 2000. In October 2001, the Company launched an underwriting initiative to meet current and future demand in the global insurance and reinsurance markets that included the recruitment of new management teams and an equity capital infusion of $763.2 million. On January 30, 2014, the Company acquired CMG Mortgage Insurance Company and its affiliated mortgage insurance companies (together, “CMG Entities”) and the mortgage insurance platform and related assets from PMI Mortgage Insurance Co., in Rehabilitation (“PMI”) (see Note 2). On March 20, 2014, the Company acquired approximately 11% of Watford Holdings Ltd.’s common equity and a warrant to purchase additional common equity for $100 million. Watford Holdings Ltd. is the parent of Watford Re Ltd., a newly-formed multi-line Bermuda reinsurance company (together with Watford Holdings Ltd., “Watford Re”). Watford Re is considered a variable interest entity (“VIE”) and the Company concluded that it is the primary beneficiary of Watford Re. As such, the results of Watford Re are included in the Company’s consolidated financial statements (see Note 4). As used herein, the “Company” means ACGL and its subsidiaries. Similarly, “Common Shares” means the common shares, par value $0.0033, of ACGL. The Company has reclassified the presentation of certain prior year information to conform to the current presentation. Such reclassifications had no effect on the Company’s net income, shareholders’ equity or cash flows. Tabular amounts are in U.S. Dollars in thousands, except share amounts, unless otherwise noted.

General

12 Months Ended

Dec. 31, 2014

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Arch Capital Group Ltd. (“ACGL”) is a Bermuda public limited liability company which provides insurance and reinsurance on a worldwide basis through its wholly owned subsidiaries. ACGL was formed in September 2000 and became the sole shareholder of Arch Capital Group (U.S.) Inc. (“Arch-U.S.”) pursuant to an internal reorganization transaction completed in November 2000. In October 2001, the Company launched an underwriting initiative to meet current and future demand in the global insurance and reinsurance markets that included the recruitment of new management teams and an equity capital infusion of $763.2 million.

On January 30, 2014, the Company acquired CMG Mortgage Insurance Company and its affiliated mortgage insurance companies (together, “CMG Entities”) and the mortgage insurance platform and related assets from PMI Mortgage Insurance Co., in Rehabilitation (“PMI”) (see Note 2).

On March 20, 2014, the Company acquired approximately 11% of Watford Holdings Ltd.’s common equity and a warrant to purchase additional common equity for $100 million. Watford Holdings Ltd. is the parent of Watford Re Ltd., a newly-formed multi-line Bermuda reinsurance company (together with Watford Holdings Ltd., “Watford Re”). Watford Re is considered a variable interest entity (“VIE”) and the Company concluded that it is the primary beneficiary of Watford Re. As such, the results of Watford Re are included in the Company’s consolidated financial statements (see Note 4).

As used herein, the “Company” means ACGL and its subsidiaries. Similarly, “Common Shares” means the common shares, par value $0.0033, of ACGL. The Company has reclassified the presentation of certain prior year information to conform to the current presentation. Such reclassifications had no effect on the Company’s net income, shareholders’ equity or cash flows. Tabular amounts are in U.S. Dollars in thousands, except share amounts, unless otherwise noted.