Argo Group International (ARGO-PA) 10-Q 7 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Aug. 03, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	AGII
Entity Registrant Name	Argo Group International Holdings, Ltd.
Entity Central Index Key	1,091,748
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		27,925,756

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	[1]
Assets
Available-for-sale (cost: 2015 - $2,759.5; 2014 - $2,817.2)	$ 2,764	$ 2,840.7
Equity securities, at fair value (cost: 2015 - $332.4; 2014 - $307.3)	486.6	486.3
Other investments (cost: 2015 - $501.1; 2014 - $488.9)	508.9	495.1
Short-term investments, at fair value (cost: 2015 - $322.7; 2014 - $275.8)	322.7	275.8
Total investments	4,082.2	4,097.9
Cash	106.5	81
Accrued investment income	20.6	22.1
Premiums receivable	448.9	353.6
Reinsurance recoverables	1,019.2	997.2
Goodwill	152.2	152.2
Intangible assets, net of accumulated amortization	76.5	78.6
Current income taxes receivable, net	6	14.9
Deferred acquisition costs, net	139.3	124.6
Ceded unearned premiums	261.9	207.6
Other assets	230.7	226.6
Total assets	6,544	6,356.3
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses	3,078.2	3,042.4
Unearned premiums	896.4	817.2
Accrued underwriting expenses	118.9	143.1
Ceded reinsurance payable, net	261.5	178.8
Funds held	58.8	55
Senior unsecured fixed rate notes	143.8	143.8
Other indebtedness	56.7	62
Junior subordinated debentures	172.7	172.7
Deferred tax liabilities, net	41.2	53
Other liabilities	46.9	41.6
Total liabilities	$ 4,875.1	$ 4,709.6
Commitments and contingencies (Note 14)
Shareholders' equity:
Common shares - $1.00 par, 500,000,000 shares authorized; 37,021,341 and 34,318,224 shares issued and outstanding at June 30, 2015 and December 31, 2014, respectively	$ 37	$ 34.3
Additional paid-in capital	960.6	836.3
Treasury shares (9,095,585 and 8,606,489 shares at June 30, 2015 and December 31, 2014, respectively)	(326.3)	(301.4)
Retained earnings	920.5	969.4
Accumulated other comprehensive income, net of taxes	77.1	108.1
Total shareholders' equity	1,668.9	1,646.7
Total liabilities and shareholders' equity	$ 6,544	$ 6,356.3
[1]	Derived from audited consolidated financial statements.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	[1]
Statement Of Financial Position [Abstract]
Available-for-sale cost	$ 2,759.5	$ 2,817.2
Equity securities cost	332.4	307.3
Other investments cost	501.1	488.9
Short-term investments, Cost	$ 322.7	$ 275.8
Common shares, par value	$ 1	$ 1
Common shares, shares authorized	500,000,000	500,000,000
Common shares, shares issued	37,021,341	34,318,224
Common shares, shares outstanding	37,021,341	34,318,224
Treasury shares, shares	9,095,585	8,606,489
[1]	Derived from audited consolidated financial statements.

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Premiums and other revenue:
Earned premiums	$ 346	$ 336.1	$ 680.6	$ 661.8
Net investment income	21.8	20.6	42.6	43.9
Net realized investment and other gains	5.3	18.5	21.3	29.6
Total revenue	373.1	375.2	744.5	735.3
Expenses:
Losses and loss adjustment expenses	190.6	185.1	374.3	367.6
Underwriting, acquisition and insurance expenses	139.5	136.8	269.1	265.5
Interest expense	4.6	5.1	9.5	10.1
Fee expense, net	0.7	0.1	1.1	1.5
Foreign currency exchange loss (gain)	3	3.4	(6.6)	3.2
Total expenses	338.4	330.5	647.4	647.9
Income before income taxes	34.7	44.7	97.1	87.4
Provision for income taxes	6.8	6.1	10.4	8.6
Net income	$ 27.9	$ 38.6	$ 86.7	$ 78.8
Net income per common share:
Basic	$ 1	$ 1.34	$ 3.09	$ 2.72
Diluted	0.98	1.32	3.03	2.67
Dividend declared per common share	$ 0.20	$ 0.16	$ 0.40	$ 0.30
Weighted average common shares:
Basic	27,948,978	28,761,138	28,038,836	28,962,406
Diluted	28,470,741	29,274,571	28,573,562	29,467,713
Net realized investment and other gains before other-than- temporary impairment losses	$ 6.7	$ 19.9	$ 23.2	$ 31
Other-than-temporary impairment losses recognized in earnings:
Other-than-temporary impairment losses on fixed maturities	(0.5)	(1.2)	(0.9)	(1.2)
Other-than-temporary impairment losses on equity securities	(0.9)	(0.2)	(1)	(0.2)
Impairment losses recognized in earnings	(1.4)	(1.4)	(1.9)	(1.4)
Net realized investment and other gains	$ 5.3	$ 18.5	$ 21.3	$ 29.6

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 27.9	$ 38.6	$ 86.7	$ 78.8
Other comprehensive income (loss):
Foreign currency translation adjustments	0.5	0.6	(2.6)	0.4
Unrealized gains on securities:
(Losses) gains arising during the year	(10.3)	49.8	(34.6)	54.9
Reclassification adjustment for gains included in net income	(9.5)	(16.1)	(7)	(16.2)
Other comprehensive (loss) income before tax	(19.3)	34.3	(44.2)	39.1
Unrealized gains (losses) on securities:
(Losses) gains arising during the year	(7.5)	11.8	(10.3)	15.6
Reclassification adjustment for gains included in net income	(2.8)	(3)	(2.9)	(3.1)
Income tax (benefit) provision related to other comprehensive (loss) income	(10.3)	8.8	(13.2)	12.5
Other comprehensive (loss) income, net of tax	(9)	25.5	(31)	26.6
Comprehensive income	$ 18.9	$ 64.1	$ 55.7	$ 105.4

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 86.7		$ 78.8
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and depreciation	19.6		18
Share-based payments expense	12.9		11.2
Excess tax benefit from share-based payment arrangements	(0.1)		0
Deferred income tax provision, net	1.6		4.3
Net realized investment and other gains	(21.3)		(29.6)
Loss on disposals of fixed assets, net	0.2		0
Change in:
Accrued investment income	1.5		1.5
Receivables	(120.4)		169
Deferred acquisition costs	(15)		(8.6)
Ceded unearned premiums	(56)		(47.3)
Reserves for losses and loss adjustment expenses	41.1		(145.4)
Unearned premiums	82.7		58.6
Ceded reinsurance payable and funds held	87.4		(141.9)
Income taxes	8.7		(13.2)
Accrued underwriting expenses	(31.7)		(3.1)
Other, net	(3.3)		24.2
Cash provided (used) by operating activities	94.6		(23.5)
Cash flows from investing activities:
Sales of fixed maturity investments	564.1		558
Maturities and mandatory calls of fixed maturity investments	382.6		156.8
Sales of equity securities	33.6		56.7
Sales of other investments	46.2		17.6
Purchases of fixed maturity investments	(907.6)		(718.9)
Purchases of equity securities	(48)		(12.9)
Purchases of other investments	(61.7)		(34.4)
Change in foreign regulatory deposits and voluntary pools	6.8		21.6
Change in short-term investments	(47.5)		28.9
Settlements of foreign currency exchange forward contracts	(4.6)		0.1
Purchases of fixed assets	(14.4)		(18.9)
Other, net	18.6		(15.1)
Cash (used) provided by investing activities	(31.9)		39.5
Cash flows from financing activities:
Activity under stock incentive plans	(1.4)		2.3
Repurchase of Company's common shares	(24.9)		(31.2)
Excess tax expense from share-based payment arrangements	0.1		0
Payment of cash dividends to common shareholders	(11.2)		(8.7)
Cash used by financing activities	(37.4)		(37.6)
Effect of exchange rate changes on cash	0.2		0.4
Change in cash	25.5		(21.2)
Cash, beginning of period	81	[1]	157.4
Cash, end of period	$ 106.5		$ 136.2
[1]	Derived from audited consolidated financial statements.

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	1. Basis of Presentation The accompanying consolidated financial statements of Argo Group International Holdings, Ltd. (“Argo Group,” “we” or the “Company”) and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. The preparation of interim 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 financial statements and reported amounts of revenues and expenses during the reporting period. The major estimates reflected in our consolidated financial statements include, but are not limited to, reserves for losses and loss adjustment expenses; reinsurance recoverables, including the reinsurance recoverables allowance for doubtful accounts; estimates of written and earned premiums; reinsurance premium receivable; fair value of investments and assessment of potential impairment; valuation of goodwill and intangibles and our deferred tax asset valuation allowance. Actual results could differ from those estimates. Certain financial information that normally is included in annual financial statements, including certain financial statement footnotes, prepared in accordance with GAAP, is not required for interim reporting purposes and has been condensed or omitted. These statements should be read in conjunction with the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission on February 27, 2015. The interim financial information as of, and for the three and six months ended, June 30, 2015 and 2014 is unaudited. However, in the opinion of management, the interim information includes all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the results presented for the interim periods. The operating results for the interim periods are not necessarily indicative of the results to be expected for the full year. All significant intercompany amounts have been eliminated in consolidation. Certain amounts in prior years’ financial statements have been reclassified to conform to the current presentation. 10% Stock Dividend On February 17, 2015, our Board of Directors declared a 10% stock dividend, payable on March 16, 2015, to shareholders of record at the close of business on March 2, 2015. As a result of the stock dividend, 2,554,506 additional shares were issued. Cash was paid in lieu of fractional shares of our common shares. All references to share and per share amounts in this document and related disclosures have been adjusted to reflect the stock dividend for all periods presented.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2015
Accounting Changes And Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	2 . Recently Issued Accounting Pronouncements In May 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” (Topic 606). The ASU is a comprehensive new revenue recognition model that requires a company to recognize revenue to depict the transfer of goods or services to a customer at an amount that reflects the consideration it expects to receive in exchange for those goods or services. The ASU provides a five-step analysis of transactions to determine when and how revenue is recognized and requires additional disclosures sufficient to describe the nature, amount, timing and uncertainty of revenue and cash flows for these transactions. This ASU is effective for annual reporting periods beginning after December 15, 2016 and early adoption is not permitted. Accordingly, we will adopt this ASU on January 1, 2017. On April 1, 2015 the FASB voted to propose to defer ASU 2014-09 for one year, which if accepted, would delay our adoption date until January 1, 2018. Companies may use either a “full retrospective” adoption, meaning the update is applied to all periods presented, or a “modified retrospective” adoption, meaning the update is applied only to the most current period presented in the financial statements. While insurance contracts are excluded from this ASU, fee income related to our brokerage operations and management of the third-party capital for our underwriting Syndicate at Lloyd’s will be subject to this updated guidance. We are currently evaluating what impact this ASU will have on our financial results and disclosures and which adoption method to apply. In February 2015, the FASB issued ASU 2015-02, "Consolidation (Topic 810): Amendments to the Consolidation Analysis." ASU 2015-02 changes the analysis that a reporting entity must perform to determine whether entities should be consolidated if they are deemed variable interest entities. It is effective for annual reporting periods, and interim periods within those years, beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. We are currently in the process of evaluating the impact of the adoption of ASU 2015-02 on our consolidated financial statements . In May 2015, the FASB issued ASU 2015-09, “Insurance (Topic 944), Disclosures about Short-Duration Contracts.” ASU 2015-09 requires additional disclosures about short-duration contracts for products in effect for typically a year or less. The disclosures will focus on the liability for unpaid claims and claim adjustment expenses. ASU 2015-09 is effective for annual periods beginning after December 15, 2015 and interim periods within annual periods beginning after December 15, 2016. We are currently in the process of evaluating the impact of the adoption of ASU 2015-09 on our consolidated financial statements.

Investments

Investments	6 Months Ended
	Jun. 30, 2015
Investments Debt And Equity Securities [Abstract]
Investments	3 . Investments Composition of Invested Assets The amortized cost, gross unrealized gains, gross unrealized losses and fair value of investments were as follows: June 30, 2015 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities USD denominated: U.S. Governments $ 183.9 $ 1.2 $ 0.1 $ 185.0 Non-U.S. Governments 84.7 0.4 0.7 84.4 Obligations of states and political subdivisions 477.1 17.3 1.6 492.8 Credit-Financial 461.7 9.7 1.8 469.6 Credit-Industrial 430.4 7.5 2.4 435.5 Credit-Utility 143.8 2.9 2.4 144.3 Structured securities: CMO/MBS-agency (1) 143.0 6.4 0.4 149.0 CMO/MBS-non agency 12.1 0.8 — 12.9 CMBS (2) 161.9 1.1 0.7 162.3 ABS (3) 245.4 1.2 0.7 245.9 Foreign denominated: Governments 175.9 1.9 13.7 164.1 Credit 239.6 3.5 24.9 218.2 Total fixed maturities 2,759.5 53.9 49.4 2,764.0 Equity securities 332.4 164.5 10.3 486.6 Other investments 501.1 10.3 2.5 508.9 Short-term investments 322.7 — — 322.7 Total investments $ 3,915.7 $ 228.7 $ 62.2 $ 4,082.2 (1) (2) (3) December 31, 2014 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities USD denominated: U.S. Governments $ 184.0 $ 1.3 $ 0.3 $ 185.0 Non-U.S. Governments 79.9 0.6 0.6 79.9 Obligations of states and political subdivisions 468.1 22.9 0.3 490.7 Credit-Financial 508.1 12.3 2.3 518.1 Credit-Industrial 493.7 9.4 3.5 499.6 Credit-Utility 142.7 3.2 3.9 142.0 Structured securities: CMO/MBS-agency (1) 168.0 8.0 0.7 175.3 CMO/MBS-non agency 13.2 0.8 — 14.0 CMBS (2) 178.6 1.6 0.2 180.0 ABS (3) 221.4 0.6 1.0 221.0 Foreign denominated: Governments 148.4 1.2 9.4 140.2 Credit 211.1 2.7 18.9 194.9 Total fixed maturities 2,817.2 64.6 41.1 2,840.7 Equity securities 307.3 184.1 5.1 486.3 Other investments 488.9 7.5 1.3 495.1 Short-term investments 275.8 — — 275.8 Total investments $ 3,889.2 $ 256.2 $ 47.5 $ 4,097.9 (1) (2) (3) Included in “Total investments” in our Consolidated Balance Sheets at June 30, 2015 and December 31, 2014 is $78.3 million and $75.2 million, respectively, of assets managed on behalf of the trade capital providers, who are third-party participants that provide underwriting capital to our Syndicate 1200 segment. Contractual Maturity The amortized cost and fair values of fixed maturity investments as of June 30, 2015, by contractual maturity, were as follows: (in millions) Amortized Cost Fair Value Due in one year or less $ 252.7 $ 245.9 Due after one year through five years 1,207.9 1,208.7 Due after five years through ten years 555.0 557.2 Thereafter 181.5 182.1 Structured securities 562.4 570.1 Total $ 2,759.5 $ 2,764.0 The expected maturities may differ from the contractual maturities because debtors may have the right to call or prepay obligations. Other Invested Assets Details regarding the carrying value and unfunded investment commitments of the other invested assets portfolio as of June 30, 2015 and December 31, 2014 were as follows: June 30, 2015 (in millions) Carrying Value Unfunded Commitments Investment Type Hedge funds $ 145.6 $ — Private equity 141.8 74.5 Long only funds 202.7 — Other investments 18.8 — Total other invested assets $ 508.9 $ 74.5 December 31, 2014 (in millions) Carrying Value Unfunded Commitments Investment Type Hedge funds $ 153.2 $ — Private equity 123.6 72.9 Long only funds 200.7 — Other investments 17.6 — Total other invested assets $ 495.1 $ 72.9 The following describes each investment type: · Hedge funds: Hedge funds include equity long/short, multi-strategy credit, relative value credit and distressed event credit funds. · Private equity: Private equity includes buyout funds, real asset/infrastructure funds, credit special situations funds, mezzanine lending funds and direct investments and strategic non-controlling minority investments in private companies that are principally accounted for using the equity method of accounting. · Long only funds: These funds include a long-only fund that invests in high yield fixed income securities and funds that primarily invest in investment-grade corporate and sovereign fixed income securities. · Other investments: Other investments include assets on deposit with various regulatory authorities to support Syndicate 1200 segment’s insurance and reinsurance operations and foreign exchange currency forward contracts to manage exposure on losses related to global catastrophic events, our Canadian dollar investment portfolio and certain Euro denominated investments. Unrealized Losses and Other-than-temporary Impairments An aging of unrealized losses on our investments in fixed maturities, equity securities, other investments and short-term investments is presented below: June 30, 2015 Less Than One Year One Year or Greater Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturities USD denominated: U.S. Governments (2) $ 17.8 $ 0.1 $ 4.1 $ — $ 21.9 $ 0.1 Non-U.S. Governments 27.6 0.6 2.7 0.1 30.3 0.7 Obligations of states and political subdivisions 80.6 1.2 9.0 0.4 89.6 1.6 Credit-Financial 203.0 1.7 10.6 0.1 213.6 1.8 Credit-Industrial 167.8 1.9 17.8 0.5 185.6 2.4 Credit-Utility 63.8 2.3 1.5 0.1 65.3 2.4 Structured securities: CMO/MBS-agency 11.1 0.1 7.9 0.3 19.0 0.4 CMBS (2) 40.2 0.7 3.6 — 43.8 0.7 ABS 88.0 0.4 10.5 0.3 98.5 0.7 Foreign denominated: Governments 127.9 13.7 — — 127.9 13.7 Credit (2) 198.6 24.9 0.9 — 199.5 24.9 Total fixed maturities 1,026.4 47.6 68.6 1.8 1,095.0 49.4 Equity securities 90.1 10.3 — — 90.1 10.3 Other investments (2.2 ) 2.5 — — (2.2 ) 2.5 Short-term investments (1) 17.8 — — — 17.8 — Total $ 1,132.1 $ 60.4 $ 68.6 $ 1.8 $ 1,200.7 $ 62.2 (1) (2) December 31, 2014 Less Than One Year One Year or Greater Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturities USD denominated: U.S. Governments $ 55.0 $ 0.2 $ 15.7 $ 0.1 $ 70.7 $ 0.3 Non-U.S. Governments 36.5 0.4 5.2 0.2 41.7 0.6 Obligations of states and political subdivisions 10.4 0.1 16.6 0.2 27.0 0.3 Credit-Financial 195.7 2.2 11.1 0.1 206.8 2.3 Credit-Industrial 240.8 3.3 12.2 0.2 253.0 3.5 Credit-Utility 63.1 3.8 1.9 0.1 65.0 3.9 Structured securities: CMO/MBS-agency 10.1 0.1 19.2 0.6 29.3 0.7 CMBS 49.3 0.1 6.0 0.1 55.3 0.2 ABS 129.2 0.7 8.1 0.3 137.3 1.0 Foreign denominated: Governments 123.7 9.3 11.2 0.1 134.9 9.4 Credit 190.8 18.7 0.9 0.2 191.7 18.9 Total fixed maturities 1,104.6 38.9 108.1 2.2 1,212.7 41.1 Equity securities 53.6 5.1 — — 53.6 5.1 Other investments (0.9 ) 1.3 — — (0.9 ) 1.3 Short-term investments — — — — — — Total $ 1,157.3 $ 45.3 $ 108.1 $ 2.2 $ 1,265.4 $ 47.5 We regularly evaluate our investments for other than temporary impairment. For fixed maturity securities, the evaluation for a credit loss is generally based on the present value of expected cash flows of the security as compared to the amortized book value. For structured securities, frequency and severity of loss inputs are used in projecting future cash flows of the securities. Loss frequency is measured as the credit default rate, which includes such factors as loan-to-value ratios and credit scores of borrowers. For equity securities and other investments, the length of time and the amount of decline in fair value are the principal factors in determining other-than-temporary impairment. We also recognize other-than-temporary losses on fixed maturity securities that we intend to sell. We hold a total of 6,517 securities, of which 2,338 were in an unrealized loss position for less than one year and 104 were in an unrealized loss position for a period one year or greater as of June 30, 2015. Unrealized losses greater than twelve months on fixed maturities were the result of a number of factors, including increased credit spreads, foreign currency fluctuations and higher market yields relative to the date the securities were purchased, and for structured securities, by the performance of the underlying collateral, as well. In considering whether an investment is other-then-temporarily impaired or not, we also considered that we do not intend to sell the investments and it is unlikely that we will be required to sell the investments before recovery of their amortized cost bases, which may be maturity. In situations where we did not recognize other-than-temporary losses on investments in our equity portfolio, we have evaluated the near-term prospects of the investment in relation to the severity and duration of the impairment and based on that evaluation, have the ability and intent to hold these investments until a recovery of the cost basis. We do not consider these investments to be other-than-temporarily impaired at June 30, 2015. We recognized other-than-temporary losses on our fixed maturities portfolio of $0.5 million and $0.9 million for the three and six months ended June 30, 2015, respectively. We recognized other-than-temporary losses on our fixed maturities portfolio of $1.2 million for both the three and six months ended June 30, 2014. We recognized other-than-temporary losses on our equity portfolio of $0.9 million and $1.0 million for the three and six months ended June 30, 2015, respectively. We recognized other-than-temporary losses on our equity portfolio of $0.2 million for both the three and six months ended June 30, 2014. Realized Gains and Losses The following table presents our gross realized investment gains (losses) and other: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Realized gains Fixed maturities $ 3.5 $ 6.1 $ 7.6 $ 10.7 Equity securities 9.0 8.9 12.8 15.4 Other investments 9.4 10.2 30.3 22.9 Short-term investments 1.1 0.1 1.1 0.1 Gain on sale of real estate holdings and other 0.1 — 0.4 — Gross realized investment gains 23.1 25.3 52.2 49.1 Realized losses Fixed maturities (5.3 ) (4.1 ) (9.0 ) (7.6 ) Equity securities (0.4 ) — (1.1 ) (0.1 ) Other investments (10.4 ) (1.2 ) (17.5 ) (6.1 ) Short-term investments (0.3 ) (0.1 ) (1.4 ) (0.3 ) Other assets — — — (4.0 ) Other-than-temporary impairment losses on fixed maturities (0.5 ) (1.2 ) (0.9 ) (1.2 ) Other-than-temporary impairment losses on equity securities (0.9 ) (0.2 ) (1.0 ) (0.2 ) Gross realized investment and other losses (17.8 ) (6.8 ) (30.9 ) (19.5 ) Net realized investment and other gains $ 5.3 $ 18.5 $ 21.3 $ 29.6 The cost of securities sold is based on the specific identification method. Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments are summarized as follows: (in millions) Fixed Maturities Equity Maturities Other Investments Short Term Real Estate Holdings and Other Tax Effects Total Three Months Ended June 30, 2015 Realized before impairments $ (1.8 ) $ 8.6 $ (1.0 ) $ 0.8 $ 0.1 $ (2.2 ) $ 4.5 Realized - impairments (0.5 ) (0.9 ) — — — 0.5 (0.9 ) Change in unrealized (6.0 ) (14.0 ) — 0.2 — 10.3 (9.5 ) — Three Months Ended June 30, 2014 Realized before impairments $ 2.0 $ 8.9 $ 9.0 $ — $ — $ (5.3 ) $ 14.6 Realized - impairments (1.2 ) (0.2 ) — — — 0.4 (1.0 ) Change in unrealized 13.4 18.9 1.4 — — (8.8 ) 24.9 Six Months Ended June 30, 2015 Realized before impairments $ (1.4 ) $ 11.7 $ 12.8 $ (0.3 ) $ 0.4 $ (8.4 ) $ 14.8 Realized - impairments (0.9 ) (1.0 ) — — — 0.2 (1.7 ) Change in unrealized (18.3 ) (24.9 ) 1.6 — — 13.2 (28.4 ) Six Months Ended June 30, 2014 Realized before impairments $ 3.1 $ 15.3 $ 16.8 $ (0.2 ) $ (4.0 ) $ (8.9 ) $ 22.1 Realized - impairments (1.2 ) (0.2 ) — — — 0.5 (0.9 ) Change in unrealized 22.0 15.5 1.2 — — (12.5 ) 26.2 We enter into foreign currency exchange forward contracts to manage currency exposure on losses related to certain global catastrophe events. These currency forward contracts are carried at fair value in our Consolidated Balance Sheets in “Other investments.” The realized and unrealized gains and losses on these contracts are included in “Net realized investment and other gains” in our Consolidated Statements of Income. The notional amount of these currency forward contracts was $7.7 million and $43.0 million at June 30, 2015 and 2014, respectively. The fair value of these currency forward contracts was a loss of $0.8 million and a gain of $0.6 million at June 30, 2015 and 2014, respectively. For the three and six months ended June 30, 2015, we recognized $0.2 million and $0.5 million in realized gains and $0.8 million and $2.0 million in realized losses, respectively, from these currency forward contracts. For the three and six months ended June 30, 2014, we recognized $1.2 million and $3.6 million in realized gains and $0.3 million and $1.6 million in realized losses, respectively, from these currency forward contracts. In the third quarter of 2014, we entered into foreign currency exchange forward contracts to manage currency exposure on our Canadian dollar (“CAD”) investment portfolio. The currency forward contracts are carried at fair value in our Consolidated Balance Sheets in “Other investments.” The realized and unrealized gains and losses are included in “Net realized investment and other gains” in our Consolidated Statements of Income. The notional amount of the currency forward contracts was CAD 142.7 million (USD $114.8 million) as of June 30, 2015. The fair value of the currency forward contracts was a gain of $3.0 million as of June 30, 2015. For the three and six months ended June 30, 2015, we recognized $3.6 million and $11.1 million in realized gains and $2.8 million and $4.8 million in realized losses, respectively, from the CAD currency forward contracts. In the second quarter of 2015, we entered into foreign currency exchange forward contracts to minimize negative impacts to our investment portfolio returns. These currency forward contracts are carried at fair value in our Consolidated Balance Sheets in “Other investments”. The realized and unrealized gains and losses are included in “Net realized investment and other gains” in our Consolidated Statements of Income. The notional amount of the current forward contacts was $21.1 million at June 30, 2015. The fair value of the currency forward contracts was a loss of $0.2 million at June 30, 2015. For both the three and six months ended June 30, 2015, we recognized $0.4 million in realized gains and $1.0 million in realized losses from these currency forward contracts. We also enter into foreign currency exchange forward contracts to manage currency exposure on certain Euro denominated investments. The currency forward contracts are carried at fair value in our Consolidated Balance Sheets in “Other investments.” The realized and unrealized gains and losses are included in “Net realized investment and other gains” in our Consolidated Statements of Income. The fair value of the currency forward contracts was a loss of $1.0 million and $0.2 million as of June 30, 2015 and 2014, respectively. For the three and six months ended June 30, 2015, we recognized $2.4 million in realized losses and $6.3 million in realized gains, respectively, from the currency forward contracts. For the three and six months ended June 30, 2014, we recognized $0.5 million and $0.6 million in realized gains and $0.5 million and $0.6 million in realized losses, respectively, from these currency forward contracts. Regulatory Deposits, Pledged Securities and Letters of Credit At June 30, 2015, the amortized cost and fair value of investments on deposit with U.S., Canadian and various agencies for regulatory purposes were $186.2 million and $191.6 million, respectively. At December 31, 2014, the amortized cost and fair value of investments on deposit with U.S., Canadian and various agencies for regulatory purposes were $186.6 million and $194.2 million, respectively. At June 30, 2015, investments with an amortized cost of $41.6 million and fair value of $41.8 million were pledged as collateral in support of irrevocable letters of credit (“LOCs”) in the amount of $32.1 million issued under the terms of certain reinsurance agreements in respect of reported loss and loss expense reserves. At December 31, 2014, investments with an amortized cost of $55.0 million and fair value of $55.3 million were pledged as collateral in support of irrevocable LOCs in the amount of $43.6 million issued under the terms of certain reinsurance agreements in respect of reported loss and loss expense reserves. Our Corporate member’s capital supporting our Lloyd’s business was $213.0 million and $217.9 million at June 30, 2015 and December 31, 2014, respectively. Fair Value Measurements Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability, or in the absence of a principal market, the most advantageous market. Market participants are buyers and sellers in the principal (or most advantageous) market that are independent, knowledgeable, able to transact for the asset or liability and willing to transfer the asset or liability. Valuation techniques consistent with the market approach, income approach and/or cost approach are used to measure fair value. The inputs of these valuation techniques are categorized into three levels. ● ● ● We receive fair value prices from third-party pricing services and our outside investment managers. These prices are determined using observable market information such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things. We have reviewed the processes used by the third-party providers for pricing the securities, and have determined that these processes result in fair values consistent with GAAP requirements. In addition, we review these prices for reasonableness, and have not adjusted any prices received from the third-party providers as of June 30, 2015. A description of the valuation techniques we use to measure assets at fair value is as follows: Fixed Maturities (Available-for-Sale) Levels 1 and 2: ● ● ● Equity Securities Level 1: Equity securities are principally reported at fair value using Level 1 inputs. For these securities, we obtain fair value measurements from a third-party pricing service using quoted prices (unadjusted) in active markets at the reporting date. Equity Securities Level 3: We own certain equity securities that are reported at fair value using Level 3 inputs. The valuation techniques for these securities include the following: — Fair value measurements are obtained from the National Association of Insurance Commissioners’ Security Valuation Office at the reporting date. — Fair value measurements for an investment in an equity fund obtained by applying final prices provided by the administrator of the fund, which is based upon certain estimates and assumptions. Other Investments Level 2: Foreign regulatory deposits are assets held in trust in jurisdictions where there is a legal and regulatory requirement to maintain funds locally in order to protect policyholders. Lloyd’s is the appointed investment manager for the funds. These assets are invested in short-term government securities, agency securities and corporate bonds and are valued using Level 2 inputs based upon values obtained from Lloyd’s. Foreign currency future contracts are valued by our counterparty using market driven foreign currency exchange rates and are considered Level 2 investments. Short-term Investments: Short-term investments are principally reported at fair value using Level 1 inputs, with the exception of short-term corporate bonds reported at fair value using Level 2 inputs as described in the fixed maturities section above. Values for the investments categorized as Level 1 are obtained from various financial institutions as of the reporting date. Transfers Between Level 1 and Level 2 Securities: There were no transfers between Level 1 and Level 2 securities during the three months ended June 30, 2015. Based on an analysis of the inputs, our financial assets measured at fair value on a recurring basis have been categorized as follows: Fair Value Measurements at Reporting Date Using (in millions) June 30, 2015 Level 1 (a) Level 2 (b) Level 3 (c) Fixed maturities USD denominated: U.S. Governments $ 185.0 $ 104.8 $ 80.2 $ — Non-U.S. Governments 84.4 — 84.4 — Obligations of states and political subdivisions 492.8 — 492.8 — Credit-Financial 469.6 — 469.6 — Credit-Industrial 435.5 — 435.5 — Credit-Utility 144.3 — 144.3 — Structured securities: CMO/MBS-agency 149.0 — 149.0 — CMO/MBS-non agency 12.9 — 12.9 — CMBS 162.3 — 162.3 — ABS 245.9 — 245.9 — Foreign denominated: Governments 164.1 — 164.1 — Credit 218.2 — 218.2 — Total fixed maturities 2,764.0 104.8 2,659.2 — Equity securities 486.6 485.8 — 0.8 Other investments 88.5 — 88.5 — Short-term investments 322.7 320.9 1.8 — $ 3,661.8 $ 911.5 $ 2,749.5 $ 0.8 (a) (b) (c) Fair Value Measurements at Reporting Date Using (in millions) December 31, 2014 Level 1 (a) Level 2 (b) Level 3 (c) Fixed maturities USD denominated: U.S. Governments $ 185.0 $ 99.2 $ 85.8 $ — Non-U.S. Governments 79.9 — 79.9 — Obligations of states and political subdivisions 490.7 — 490.7 — Credit-Financial 518.1 — 518.1 — Credit-Industrial 499.6 — 499.6 — Credit-Utility 142.0 — 142.0 — Structured securities: CMO/MBS-agency 175.3 — 175.3 — CMO/MBS-non agency 14.0 — 14.0 — CMBS 180.0 — 180.0 — ABS 221.0 — 221.0 — Foreign denominated: Governments 140.2 — 140.2 — Credit 194.9 — 194.9 — Total fixed maturities 2,840.7 99.2 2,741.5 — Equity securities 486.3 485.4 — 0.9 Other investments 97.3 — 97.3 — Short-term investments 275.8 273.9 1.9 — $ 3,700.1 $ 858.5 $ 2,840.7 $ 0.9 (a) (b) (c) The fair value measurements in the tables above do not equal “Total investments” on our Consolidated Balance Sheets as they exclude certain other investments that are accounted for under the equity-method of accounting. A reconciliation of the beginning and ending balances for the investments categorized as Level 3 are as follows: Fair Value Measurements Using Observable Inputs (Level 3) (in millions) Equity Securities Total Beginning balance, January 1, 2015 $ 0.9 $ 0.9 Transfers into Level 3 — — Transfers out of Level 3 — — Total gains or losses (realized/unrealized): Included in net income (loss) — — Included in other comprehensive income (loss) — — Purchases, issuances, sales, and settlements Purchases — — Issuances — — Sales (0.1 ) (0.1 ) Settlements — Ending balance, June 30, 2015 $ 0.8 $ 0.8 Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at June 30, 2015 $ — $ — (in millions) Equity Securities Other Assets Total Beginning balance, January 1, 2014 $ 1.3 $ 2.6 $ 3.9 Transfers into Level 3 — — — Transfers out of Level 3 — — — Total gains or losses (realized/unrealized): Included in net income (loss) — — — Included in other comprehensive income (loss) 0.1 — 0.1 Purchases, issuances, sales, and settlements Purchases — — — Issuances — — — Sales (0.5 ) — (0.5 ) Settlements — (2.6 ) (2.6 ) Ending balance, December 31, 2014 $ 0.9 $ — $ 0.9 Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014 $ — $ — $ — At June 30, 2015 and December 31, 2014, we did not have any financial assets or financial liabilities measured at fair value on a nonrecurring basis or any financial liabilities on a recurring basis.

Reserves for Losses and Loss Ad

Reserves for Losses and Loss Adjustment Expenses	6 Months Ended
	Jun. 30, 2015
Insurance [Abstract]
Reserves for Losses and Loss Adjustment Expenses	4 . Reserves for Losses and Loss Adjustment Expenses The following table provides a reconciliation of reserves for losses and loss adjustment expenses (“LAE”): For the Six Months Ended June 30, (in millions) 2015 2014 Net reserves beginning of the year 2,137.1 $ 2,107.6 Add: Losses and LAE incurred during current calendar year, net of reinsurance: Current accident year 383.0 390.9 Prior accident years (8.7 ) (23.3 ) Losses and LAE incurred during calendar year, net of reinsurance 374.3 367.6 Deduct: Losses and LAE payments made during current calendar year, net of reinsurance: Current accident year 52.8 71.6 Prior accident years 313.3 290.3 Losses and LAE payments made during current calendar year, net of reinsurance: 366.1 361.9 Change in participation interest (1) (1.2 ) 24.7 Foreign exchange adjustments (14.5 ) 4.4 Net reserves - end of period 2,129.6 2,142.4 Add: Reinsurance recoverables on unpaid losses and LAE, end of period 948.6 925.5 Gross reserves - end of period 3,078.2 $ 3,067.9 (1) Reserves for losses and LAE represent the estimated indemnity cost and related adjustment expenses necessary to investigate and settle claims. Such estimates are based upon individual case estimates for reported claims, estimates from ceding companies for reinsurance assumed and actuarial estimates for losses that have been incurred but not yet reported to the insurer. Any change in probable ultimate liabilities is reflected in current operating results. Impacting losses and LAE for the six months ended June 30, 2015 was $8.7 million in favorable prior years’ loss reserve development comprised of the following: $15.0 million of net favorable development in the Excess and Surplus Lines segment primarily the result of favorable development in the general and products liability lines and commercial automobile, partially offset by unfavorable development in property lines; $11.6 million of net unfavorable development in the Commercial Specialty segment, primarily driven by unfavorable development in general liability and workers compensation due to increases in claim severity, partially offset by favorable development in auto liability and short tail lines; $3.7 million of net favorable development in the International Specialty segment primarily driven by favorable development in Argo Re and long-tail lines, partially offset by unfavorable development in the Brazil unit; $2.5 million of net favorable development in the Syndicate 1200 segment primarily driven by favorable development in property and marine & energy, partially offset by unfavorable development in various liability classes; and $0.9 million of unfavorable development in the Run-off Lines segment primarily caused by unfavorable development in workers compensation lines and assumed asbestos and environmental liability, offset in part by favorable development in run-off reinsurance claims. Impacting losses and LAE for the six months ended June 30, 2014 was $23.3 million in favorable prior years’ loss reserve development comprised of the following: $21.7 million of net favorable development in the Excess and Surplus Lines segment primarily caused by favorable development in the general and products liability lines, partially offset by unfavorable development in commercial automobile and property lines; $4.9 million of net unfavorable development in the Commercial Specialty segment, primarily driven by unfavorable development in general liability due to increases in claim severity, as well as unfavorable development in auto liability, partially offset by favorable development in workers compensation and short-tail lines; $0.4 million of net unfavorable development in the International Specialty segment primarily driven by our Brazil unit; $15.2 million of net favorable development in the Syndicate 1200 segment primarily driven by favorable development in various property classes, as well as favorable development in professional indemnity and aerospace, partially offset by unfavorable development in general liability; and $8.3 million of unfavorable development in the Run-off Lines segment primarily caused by unfavorable development in workers compensation lines driven by increasing medical costs on older claims, as well as unfavorable development in asbestos liability on assumed business. In the opinion of management, our reserves represent the best estimate of our ultimate liabilities, based on currently known facts, current law, current technology and assumptions considered reasonable where facts are not known. Due to the significant uncertainties and related management judgments, there can be no assurance that future loss development, favorable or unfavorable, will not occur.

Debt

Debt	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Debt	5 . Debt Revolving Credit Facility On March 7, 2014, each of Argo Group, Argo Group US, Inc., Argo International Holdings Limited and Argo Underwriting Agency Limited (the “Borrowers”) entered into a $175 million credit agreement (“Credit Agreement”) with JPMorgan Chase Bank, N.A., as administrative agent. The Credit Agreement provides for a $175.0 million revolving credit facility with a maturity date of March 7, 2018 unless extended in accordance with the terms of the Credit Agreement. Borrowings under the Credit Agreement may be used for general corporate purposes, including working capital and permitted acquisitions, and each of the Borrowers has agreed to be jointly and severally liable for the obligations of the other Borrowers under the Credit Agreement. The Credit Agreement contains customary events of default. If an event of default occurs and is continuing, the Borrowers might be required immediately to repay all amounts outstanding under the Credit Agreement. Lenders holding at least a majority of the loans and commitments under the Credit Agreement may elect to accelerate the maturity of the loans and/or terminate the commitments under the Credit Agreement upon the occurrence and during the continuation of an event of default. Included in the Credit Agreement is a provision that allows up to $17.5 million of the revolving credit facility to be used for LOCs, subject to availability. As of June 30, 2015 and December 31, 2014, there were no borrowings outstanding and $0.2 million in LOCs against the Credit Facility. Junior Subordinated Debentures On July 16, 2014, Argo Group US, Inc. purchased the outstanding PXRE Capital Trust V $20,000,000 Junior Subordinated Debt Securities (“Capital Trust V”) at a discount equal to 90.0% of the principal amount plus accrued and unpaid interest through the date of purchase for a total price of $18.2 million, resulting in the recognition of a $2.0 million pre-tax realized gain. In accordance with ASC Topic 405, “Liabilities,” we have eliminated the recognized gain, outstanding debt, associated interest, and intercompany balances related to the purchase of the Capital Trust V since the purchase by Argo Group US, Inc., in essence, reduced our outstanding debt related to the Junior Subordinated Debentures. The Capital Trust V continued to accrue interest until it was redeemed on April 29, 2015.

Disclosures about Fair Value of

Disclosures about Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Disclosures about Fair Value of Financial Instruments	6. Disclosures about Fair Value of Financial Instruments Cash. The carrying amount approximates fair value. Investment securities and short-term investments . See Note 3, “Investments,” for additional information. Premiums receivable and reinsurance recoverables on paid losses. The carrying value of current receivables approximates fair value. At June 30, 2015 and December 31, 2014, the carrying values of premiums receivable over 90 days were $13.6 million and $12.4 million, respectively. Included in “Reinsurance recoverables” in our Consolidated Balance Sheets at June 30, 2015 and December 31, 2014, are amounts that are due from trade capital providers associated with the operations of ArgoGlobal Syndicate 1200. Upon settlement, the receivable is offset against the liability also reflected in our accompanying Consolidated Balance Sheets. At June 30, 2015 and December 31, 2014, the payable was in excess of the receivable. Of our reinsurance recoverables on paid losses, excluding amounts attributable to ArgoGlobal Syndicate 1200’s trade capital providers, at June 30, 2015 and December 31, 2014, the carrying values over 90 days were $11.3 million and $9.9 million, respectively. Our methodology for establishing our allowances for doubtful accounts includes specifically identifying all potential uncollectible balances regardless of aging. At June 30, 2015 and December 31, 2014, the allowance for doubtful accounts for premiums receivable was $3.8 million and $5.2 million, respectively, and the allowance for doubtful accounts for reinsurance recoverables on paid losses was $2.5 million and $1.8 million, respectively. Premiums receivable over 90 days were secured by collateral in the amount of $0.3 million and $0.3 million at June 30, 2015 and December 31, 2014, respectively. Reinsurance recoverables on paid losses over 90 days were secured by collateral in the amount of $0.6 million and $0.4 at June 30, 2015 and December 31, 2014, respectively. At June 30, 2015 and December 31, 2014, the fair value of our Junior subordinated debentures, Senior unsecured fixed rate notes and Other indebtedness was estimated using appropriate market indices or quoted prices from external sources based on current market conditions. A summary of our financial instruments whose carrying value did not equal fair value is shown below: June 30, 2015 December 31, 2014 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Junior subordinated debentures $ 172.7 $ 156.6 $ 172.7 $ 155.5 Senior unsecured fixed rate notes 143.8 145.0 143.8 132.3 Other indebtedness: Floating rate loan stock 56.1 50.8 61.3 55.2 Note payable 0.6 0.6 0.7 0.6 $ 373.2 $ 353.0 $ 378.5 $ 343.6

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Shareholders' Equity	7 . Shareholders’ Equity On August 4, 2015, our Board of Directors declared a quarterly cash dividend in the amount of $0.20 on each share of common stock outstanding.. The dividend will be paid on September 15, 2015, to shareholders of record on September 1, 2015. On February 17, 2015, our Board of Directors declared a 10% stock dividend, payable on March 16, 2015, to shareholders of record at the close of business on March 2, 2015. As a result of the stock dividend, 2,554,506 additional shares were issued. Cash was paid in lieu of fractional shares of our common shares. All references to share and per share amounts in this document and related disclosures have been adjusted to reflect the stock dividend for all periods presented. On May 5, 2015, our Board of Directors declared a quarterly cash dividend in the amount of $0.20 on each share of common stock outstanding. On June 15, 2015, we paid $5.6 million to our shareholders of record on June 1, 2015. On May 5, 2014, our Board of Directors declared a quarterly cash dividend in the amount of $0.16 on each share of common stock outstanding, on a post-stock dividend basis. On June 16, 2014, we paid $4.7 million to our shareholders of record on June 2, 2014. On November 5, 2013, our Board of Directors authorized the repurchase of up to $150.0 million of our common shares (“2013 Repurchase Authorization”). The 2013 Repurchase Authorization supersedes all the previous Repurchase Authorizations. As of June 30, 2015, availability under the 2013 Repurchase Authorization for future repurchases of our common shares was $67.9 million. For the three and six months ended June 30, 2015, we repurchased a total of 136,042 common shares and 489,096, respectively, for $6.8 million and $24.9 million, respectively. For the three and six months ended June 30, 2015, we repurchased 24,700 common shares and 221,564 on the open market, respectively, for $1.3 million and $11.2 million, respectively. In 2015, we repurchased shares under Securities Exchange Act of 1934 Rule 10b5-1 trading plans as follows: Date Trading Plan Initiated 2015 Purchase Period Number of Shares Repurchased Average Price of Shares Repurchased Total Cost (in millions) Repurchase Authorization Year 12/15/2014 01/05/2015-02/12/2015 117,482 $ 53.50 $ 6.3 2013 03/16/2015 03/18/2015-05/06/2015 150,050 $ 49.53 $ 7.4 2013

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	8 . Accumulated Other Comprehensive Income (Loss) A summary of changes in accumulated other comprehensive income (loss), net of taxes (where applicable) by component for the six months ended June 30, 2015 and 2014 is presented below: (in millions) Foreign Currency Translation Adjustments Unrealized Holding Gains on Securities Defined Benefit Pension Plans Total Balance, January 1, 2015 $ (15.6 ) $ 130.7 $ (7.0 ) $ 108.1 Other comprehensive loss before reclassifications (2.6 ) (24.3 ) — (26.9 ) Amounts reclassified from accumulated other comprehensive loss — (4.1 ) — (4.1 ) Net current-period other comprehensive loss (2.6 ) (28.4 ) — (31.0 ) Balance at June 30, 2015 $ (18.2 ) $ 102.3 $ (7.0 ) $ 77.1 (in millions) Foreign Currency Translation Adjustments Unrealized Holding Gains on Securities Defined Benefit Pension Plans Total Balance, January 1, 2014 $ (11.5 ) $ 163.9 $ (4.6 ) $ 147.8 Other comprehensive income before reclassifications 0.4 39.3 — 39.7 Amounts reclassified from accumulated other comprehensive income — (13.1 ) — (13.1 ) Net current-period other comprehensive income 0.4 26.2 — 26.6 Balance at June 30, 2014 $ (11.1 ) $ 190.1 $ (4.6 ) $ 174.4 The following tables illustrate the amounts reclassified from accumulated other comprehensive (loss) income shown in the above tables that have been included in our Consolidated Statements of Income: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Unrealized gains and losses on securities: Net realized investment losses $ (9.5 ) $ (16.1 ) $ (7.0 ) $ (16.2 ) Benefit for income taxes 2.8 3.0 2.9 3.1 Net of taxes $ (6.7 ) $ (13.1 ) $ (4.1 ) $ (13.1 )

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Net Income Per Common Share	9. Net Income Per Common Share The following table presents the calculation of net income per common share on a basic and diluted basis (all balances have been adjusted to reflect the 10% stock dividend): For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions, except number of shares and per share amounts) 2015 2014 2015 2014 Net income $ 27.9 $ 38.6 $ 86.7 $ 78.8 Weighted average common shares outstanding - basic 27,948,978 28,761,138 28,038,836 28,962,406 Effect of dilutive securities: Equity compensation awards 521,763 513,433 534,726 505,307 Weighted average common shares outstanding - diluted 28,470,741 29,274,571 28,573,562 29,467,713 Net income per common share: Basic $ 1.00 $ 1.34 $ 3.09 $ 2.72 Diluted $ 0.98 $ 1.32 $ 3.03 $ 2.67 Excluded from the weighted average common shares outstanding calculation at June 30, 2015, and 2014 are 9,095,585 shares and 8,233,645 shares, respectively, which are held as treasury shares. The shares are excluded as of their repurchase date. For the three and six months ended June 30, 2015, equity compensation awards to purchase 484 shares of common stock were excluded from the computation of diluted net income per common share as these instruments were anti-dilutive. These instruments expired during the second quarter 2015. For the three and six months ended June 30, 2014, equity compensation awards to purchase 2,611 shares of common stock were excluded from the computation of diluted net income per common share as these instruments were anti-dilutive. These instruments expired or will expire at varying times from 2014 through 2016.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2015
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	10 . Supplemental Cash Flow Information Income taxes paid. We paid income taxes of $10.5 million and $15.6 million during the six months ended June 30, 2015 and 2014, respectively. Income taxes recovered . During the six months ended June 30, 2015, $11.5 million of income taxes was recovered. No income taxes were recovered during the six months ended June 30, 2014. Interest paid. For the Six Months Ended June 30, (in millions) 2015 2014 Senior unsecured fixed rate notes $ 4.7 $ 4.7 Junior subordinated debentures 3.5 3.9 Other indebtedness 1.2 1.4 Total interest paid $ 9.4 $ 10.0

Share-based Compensation

Share-based Compensation	6 Months Ended
	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based Compensation	11. Share-based Compensation The fair value method of accounting is used for equity-based compensation plans. Under the fair value method, compensation cost is measured based on the fair value of the award at the measurement date and recognized over the requisite service period. We use the Black-Scholes model to estimate the fair values on the measurement date for share options and share appreciation rights (“SARs”). The Black-Scholes model uses several assumptions to value a share award. The volatility assumption is based on the historical change in our stock price over the previous five years preceding the measurement date. The risk-free rate of return assumption is based on the five-year U.S. Treasury constant maturity rate on the measurement date. The expected award life is based upon the average holding period over the history of the incentive plan. The expected dividend yield is based on our history and expected dividend payouts. The following table summarizes the assumptions we used for the six months ended June 30, 2015 and 2014: For the Six Months Ended June 30, 2015 2014 Risk-free rate of return 1.70% 1.64% Expected dividend yields 1.57% 1.55% Expected award life (years) 4.62 4.71 Expected volatility 21.10% 23.41% All outstanding awards were adjusted to reflect the 10% stock dividend, resulting in a 10% increase to the number of awards outstanding and a 9.09% reduction in the exercise price. Argo Group’s Long-Term Incentive Plans In November 2007, our shareholders approved the 2007 Long-Term Incentive Plan (the “2007 Plan”), which provides for an aggregate of 4.5 million shares of our common stock that may be issued to executives, non-employee directors, and other key employees. As of May 2014, 1.46 million shares remained available for grant under the 2007 Plan. In May 2014, our shareholders approved the 2014 Long-Term Incentive Plan (the “2014 Plan”), which provides for an additional 2.8 million shares of our common stock to be available for issuance to executives, non-employee directors and other key employees. The share awards may be in the form of share options, SARs, restricted shares, restricted share awards, restricted share units awards, performance awards, other share-based awards and other cash-based awards. Shares issued under this plan may be shares that are authorized and unissued or shares that we reacquired, including shares purchased on the open market. Share options and SARs will count as one share for the purposes of the limits under the incentive plans; restricted shares, restricted share units, performance units, performance shares or other share-based incentive awards which settle in common shares will count as 2.75 shares for purpose of the limits under the 2014 Plan. Share options may be in the form of incentive share options, non-qualified share options and restorative options. Share options are required to have an exercise price that is not less than the market value on the date of grant. We are prohibited from repricing the options. The term of the share options cannot exceed seven years from the grant date. A summary of restricted share activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Grant Date Fair Value Outstanding at January 1, 2015 313,716 $ 31.38 Granted 297,873 $ 39.21 Vested and issued (118,882 ) $ 26.78 Expired or forfeited (8,938 ) $ 41.76 Outstanding at June 30, 2015 483,769 $ 37.14 The restricted shares vest over two to four years. Expense recognized under this plan for the restricted shares was $1.5 million and $3.0 million for the three and six months ended June 30, 2015, respectively, as compared to $0.7 million and $1.4 million for the three and six months ended June 30, 2014, respectively. Compensation expense for all share-based compensation awards is included in “Underwriting, acquisition and insurance expense” in the accompanying Consolidated Statements of Income. As of June 30, 2015, there was $15.5 million of total unrecognized compensation cost related to restricted share compensation arrangements granted by Argo Group. A summary of stock-settled SARs activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Exercise Price Outstanding at January 1, 2015 1,313,726 $ 28.57 Granted 243,305 $ 39.43 Exercised (78,022 ) $ 26.26 Expired or forfeited (7,231 ) $ 31.68 Outstanding at June 30, 2015 1,471,778 $ 29.67 The stock-settled SARs vest over a one to four year period. Upon exercise of the stock-settled SARs, the employee is entitled to receive shares of our common stock equal to the appreciation of the stock as compared to the exercise price. Expense recognized for the stock-settled SARs was $0.3 million and $1.0 for the three and six months ended June 30, 2015, respectively, as compared to $0.7 million and $1.3 million for the three and six months ended June 30, 2014, respectively. As of June 30, 2015, there was $3.7 million of total unrecognized compensation cost related to stock-settled SARs outstanding. A summary of cash-settled SARs activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Exercise Price Outstanding at January 1, 2015 2,001,451 $ 32.76 Granted 913,157 $ 47.48 Exercised (306,278 ) $ 29.22 Expired or forfeited (91,932 ) $ 37.22 Outstanding at June 30, 2015 2,516,398 $ 38.37 The cash-settled SARs vest over a one to four year period. Upon exercise of the cash-settled SARs, the employee is entitled to receive cash payment for the appreciation in the value of our common stock over the exercise price. We account for the cash-settled SARs as liability awards, which require the awards to be revalued at each reporting period. Expense recognized for the cash-settled SARs was $8.5 million and $11.3 million for the three and six months ended June 30, 2015, respectively, as compared to $5.3 million and $8.0 million for the three and six months ended June 30, 2014, respectively. As of June 30, 2015, there was $17.0 million of total unrecognized compensation cost related to cash-settled SARs outstanding.

Underwriting, Acquisition and I

Underwriting, Acquisition and Insurance Expenses	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Underwriting, Acquisition and Insurance Expenses	12 . Underwriting, Acquisition and Insurance Expenses Underwriting, acquisition and insurance expenses were as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Commissions $ 67.2 $ 63.3 $ 125.9 $ 118.2 General expenses 79.7 74.1 152.6 142.9 Premium taxes, boards and bureaus — 5.7 0.6 12.3 146.9 143.1 279.1 273.4 Net deferral of policy acquisition costs (7.4 ) (6.3 ) (10.0 ) (7.9 ) Total underwriting, acquisition and insurance expenses $ 139.5 $ 136.8 $ 269.1 $ 265.5 Included in general expenses for the three months ended June 30, 2015 and 2014 was $10.4 million and $6.8 million, respectively, and $15.3 million and $11.1 million for the six months ended June 30, 2015 and 2014, respectively, of expense for our total equity compensation.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	13 . Income Taxes We are incorporated under the laws of Bermuda and, under current Bermuda law, are not obligated to pay any taxes in Bermuda based upon income or capital gains. We have received an undertaking from the Supervisor of Insurance in Bermuda pursuant to the provisions of the Exempted Undertakings Tax Protection Act, 2011, which exempts us from any Bermuda taxes computed on profits, income or any capital asset, gain or appreciation or any tax in the nature of estate duty or inheritance tax, at least until the year 2035. We do not consider ourselves to be engaged in a trade or business in the United States or the United Kingdom and, accordingly, do not expect to be subject to direct United States or United Kingdom income taxation. We have subsidiaries based in the United Kingdom that are subject to the tax laws of that country. Under current law, these subsidiaries are taxed at the applicable corporate tax rates. Six of the United Kingdom subsidiaries are deemed to be engaged in business in the United States, and therefore, are subject to United States corporate tax in respect of a proportion of their United States underwriting business only. Relief is available against the United Kingdom tax liabilities in respect of overseas taxes paid that arise from the underwriting business. Corporate income tax losses incurred in the United Kingdom can be carried forward, for application against future income, indefinitely. Our United Kingdom subsidiaries file separate United Kingdom income tax returns. We have subsidiaries based in the United States that are subject to United States tax laws. Under current law, these subsidiaries are taxed at the applicable corporate tax rates. Our United States subsidiaries file a consolidated United States federal income tax return. We also have operations in Belgium, Switzerland, Brazil, France, Malta, Spain and Ireland, which also are subject to income taxes imposed by the jurisdiction in which they operate. We have operations in the United Arab Emirates, which are not subject to income tax under the laws of that country. Our income tax provision includes the following components: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Current tax provision $ 9.0 $ 2.9 $ 8.8 $ 4.3 Deferred tax (benefit) provision related to: Future tax deductions (2.9 ) 3.0 2.6 33.2 Valuation allowance change 0.7 0.2 (1.0 ) (28.9 ) Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6 Our expected income tax provision computed on pre-tax income (loss) at the weighted average tax rate has been calculated as the sum of the pre-tax income (loss) in each jurisdiction multiplied by that jurisdiction’s applicable statutory tax rate. For the three and six months ended June 30, 2015 and 2014, pre-tax income (loss) attributable to our operations and the operations’ effective tax rates were as follows: For the Three Months Ended June 30, (in millions) 2015 2014 Pre-Tax Income (Loss) Effective Tax Rate Pre-Tax Income (Loss) Effective Tax Rate Bermuda $ 18.3 0.0 % $ 25.0 0.0 % United States 20.2 27.0 % 20.9 24.1 % United Kingdom (2.9 ) -46.9 % (5.4 ) -19.4 % Belgium 0.1 16.5 % — (1) 64.2 % Brazil (1.2 ) 0.0 % 5.1 0.0 % United Arab Emirates 0.1 0.0 % (0.1 ) 0.0 % Ireland (0.1 ) 0.0 % — (1) 0.0 % Malta 0.2 0.0 % (0.6 ) 0.0 % Switzerland — (1) -36.7 % (0.2 ) 18.2 % Pre-tax income $ 34.7 $ 44.7 For the Six Months Ended June 30, (in millions) 2015 2014 Pre-Tax Income (Loss) Effective Tax Rate Pre-Tax Income (Loss) Effective Tax Rate Bermuda $ 44.0 0.0 % 46.9 0.0 % United States 48.7 23.0 % 35.7 22.7 % United Kingdom 7.2 -12.0 % 1.9 25.4 % Belgium (0.1 ) -24.2 % — (1) 43.3 % Brazil (3.0 ) 0.0 % 5.1 0.0 % United Arab Emirates 0.1 0.0 % (1.0 ) 0.0 % Ireland (0.1 ) 0.0 % — (1) 0.0 % Malta 0.3 0.0 % (1.0 ) 0.0 % Switzerland — (1) -18.6 % (0.2 ) 21.0 % Pre-tax income $ 97.1 $ 87.4 (1) A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Income tax provision at expected rate $ 6.2 $ 9.8 $ 17.4 $ 14.5 Tax effect of: Tax-exempt interest (1.0 ) (1.1 ) (1.9 ) (2.3 ) Dividends received deduction (0.6 ) (0.6 ) (1.2 ) (1.2 ) Valuation allowance change 0.7 0.2 (1.0 ) (28.9 ) Other permanent adjustments, net — (1.0 ) 0.2 (0.9 ) Adjustment for annualized rate 0.3 (2.6 ) (0.2 ) (1.8 ) United States state tax (benefit) expense — (0.1 ) (2.5 ) — Capital loss carryforward from prior merger — — — 29.8 Other foreign adjustments 0.4 — 0.1 — Prior period adjustments to deferred — (1.0 ) — (1.0 ) Prior year foreign taxes recovered — — (1.2 ) — Foreign exchange adjustments 0.6 2.3 0.4 0.1 Foreign withholding taxes 0.2 0.2 0.3 0.3 Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6 Income tax provision (benefit) - Foreign $ 1.4 $ 1.0 $ (0.8 ) $ 0.4 Income tax provision - United States, Federal 5.2 5.0 14.7 7.8 Income tax (benefit) provision - United States, state — (0.1 ) (3.8 ) 0.1 Foreign withholding tax - United States 0.2 0.2 0.3 0.3 Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6 We recognize potential accrued interest and penalties within our global operations in “Interest expense” and “Underwriting, acquisition and insurance expenses,” respectively, in our Consolidated Statements of Income. Our net deferred tax assets (liabilities) are supported by taxes paid in previous periods, reversal of taxable temporary differences and recognition of future income. Management regularly evaluates the recoverability of the deferred tax assets and makes any necessary adjustments to them based upon any changes in management’s expectations of future taxable income. Realization of deferred tax assets is dependent upon our generation of sufficient taxable income in the future to recover tax benefits that cannot be recovered from taxes paid in the carryback period, which is generally two years for net operating losses and three years for capital losses for our United States operations. At June 30, 2015, we had a total net deferred tax liability of $16.8 million prior to any valuation allowance. Management has concluded that a valuation allowance is required for a portion of the tax effected net operating loss carryforward of $17.3 million generated from a prior merger and for the tax effected net operating loss carryforward of $1.0 million from ARIS. Of the net operating carryforwards from a prior merger, $15.8 million will expire if not used by December 31, 2025 and $1.5 million will expire if not used by December 31, 2027. Of the ARIS loss carryforward, $0.2 million will expire if not used by December 31, 2027, $0.4 million will expire if not used by December 31, 2028 and $0.4 million will expire if not used by December 31, 2029. The valuation allowances have been established as Internal Revenue Code Section 382 limits the application of net operating loss and net capital loss carryforwards following an ownership change. The loss carryforwards available per year are $2.8 million as required by Internal Revenue Code Section 382. Further, due to cumulative losses since inception, management has concluded that a valuation allowance is required for the full amount of the tax effected net operating losses generated by our Brazil and Malta entities. Accordingly, a valuation allowance of $24.4 million is required as of June 30, 2015 of which $15.4 million relates to the prior merger and ARIS loss carryforwards, $7.2 million relates to Brazil operations, and $1.8 million relates to Malta operations. For the six months ended June 30, 2015, the valuation allowance was reduced by $0.5 million pertaining to the prior merger and ARIS loss carryforwards, decreased by $0.2 million pertaining to our Brazil operations and decreased by $0.3 million pertaining to our Malta operations. We had no material unrecognized tax benefits as of June 30, 2015 and 2014. Our United States subsidiaries are no longer subject to U.S. federal and state income tax examinations by tax authorities for years before 2011. Our United Kingdom subsidiaries are no longer subject to United Kingdom income tax examinations by Her Majesty’s Revenue and Customs for years before 2012.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2015
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	14 . Commitments and Contingencies Argo Group’s subsidiaries are parties to legal actions incidental to their business. Based on the opinion of counsel, management believes that the resolution of these matters will not materially affect our financial condition or results of operations. We have contractual commitments to invest up to $74.5 million related to our limited partnership investments at June 30, 2015. These commitments will be funded as required by the partnership agreements.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2015
Segment Reporting [Abstract]
Segment Information	15 . Segment Information We are primarily engaged in underwriting property and casualty insurance and reinsurance. We have four ongoing reporting segments: Excess and Surplus Lines, Commercial Specialty, International Specialty and Syndicate 1200. Additionally, we have a Run-off Lines segment for certain products that we no longer underwrite. We consider many factors, including the nature of each segment’s insurance and reinsurance products, production sources, distribution strategies and the regulatory environment, in determining how to aggregate reporting segments. In evaluating the operating performance of our segments, we focus on core underwriting and investing results before the consideration of realized gains or losses from the sales of investments. Realized investment gains are reported as a component of the Corporate and Other segment, as decisions regarding the acquisition and disposal of securities reside with the investment function and are not under the control of the individual business segments. Identifiable assets by segment are those assets used in the operation of each segment. Revenue and income (loss) before income taxes for each segment were as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Revenue: Earned premiums Excess and Surplus Lines $ 131.1 $ 125.3 $ 254.2 $ 242.7 Commercial Specialty 71.7 71.1 144.3 142.8 International Specialty 38.3 37.6 75.6 74.6 Syndicate 1200 104.5 102.2 206.4 201.5 Run-off Lines 0.4 (0.1 ) 0.1 0.2 Total earned premiums 346.0 336.1 680.6 661.8 Net investment income Excess and Surplus Lines 9.0 9.0 17.5 18.3 Commercial Specialty 4.7 4.6 9.2 9.3 International Specialty 3.0 2.0 5.9 3.8 Syndicate 1200 2.4 2.1 4.6 5.8 Run-off Lines 2.1 2.3 4.1 4.8 Corporate and Other 0.6 0.6 1.3 1.9 Total net investment income 21.8 20.6 42.6 43.9 Net realized investment and other gains 5.3 18.5 21.3 29.6 Total revenue $ 373.1 $ 375.2 $ 744.5 $ 735.3 For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Income (loss) before income taxes Excess and Surplus Lines $ 24.2 $ 28.2 $ 48.9 $ 48.3 Commercial Specialty 4.6 (0.5 ) 8.4 1.2 International Specialty 8.8 5.6 17.9 12.4 Syndicate 1200 10.1 10.1 21.1 25.9 Run-off Lines (1.1 ) (3.4 ) 0.1 (9.3 ) Total segment income before taxes 46.6 40.0 96.4 78.5 Corporate and Other (17.2 ) (13.8 ) (20.6 ) (20.7 ) Net realized investment and other gains 5.3 18.5 21.3 29.6 Total income before income taxes $ 34.7 $ 44.7 $ 97.1 $ 87.4 The table below presents earned premiums by geographic location for the three and six months ended June 30, 2015 and 2014. For this disclosure, we determine geographic location by the country of domicile of our subsidiaries that underwrite the business and not by the location of insureds or reinsureds from whom the business was generated. For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Bermuda $ 26.1 $ 24.3 $ 50.0 $ 48.7 Brazil 11.9 11.8 24.4 24.4 Malta 0.4 0.6 0.9 1.1 United Kingdom 104.5 102.6 206.4 201.5 United States 203.1 196.8 398.9 386.1 Total earned premiums $ 346.0 $ 336.1 $ 680.6 $ 661.8 The following table represents identifiable assets: June 30, December 31, (in millions) 2015 2014 Excess and Surplus Lines $ 2,411.2 $ 2,350.7 Commercial Specialty 1,358.2 1,358.5 International Specialty 836.3 776.8 Syndicate 1200 1,316.4 1,258.5 Run-off Lines 577.0 552.8 Corporate and Other 44.9 59.0 Total $ 6,544.0 $ 6,356.3 Included in total assets at June 30, 2015 and December 31, 2014 are $341.6 million and $315.4 million, respectively, in assets associated with trade capital providers.

Information Provided in Connect

Information Provided in Connection with Outstanding Debt of Subsidiaries	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Information Provided in Connection with Outstanding Debt of Subsidiaries	16 . Information Provided in Connection with Outstanding Debt of Subsidiaries The following tables present condensed consolidating financial information at June 30, 2015 and December 31, 2014 and for the three and six months ended June 30, 2015 and 2014, for Argo Group (the “Parent Guarantor”) and Argo Group US (the “Subsidiary Issuer”). The Subsidiary Issuer is an indirect wholly subsidiary of the Parent Guarantor. Investments in subsidiaries are accounted for by the Parent Guarantor under the equity method for purposes of the supplemental consolidating presentation. Earnings of subsidiaries are reflected in the Parent Guarantor’s investment accounts and earnings. The Parent Guarantor fully and unconditionally guarantees certain of the debt of the Subsidiary Issuer. Condensed consolidating financial information of the Subsidiary Issuer is presented on a consolidated basis and consists principally of the net assets, results of operations and cash flows of operating insurance company subsidiaries. CONDENSED CONSOLIDATING BALANCE SHEET JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Assets Investments $ 3.7 $ 2,785.6 $ 1,292.9 $ — $ 4,082.2 Cash — 72.4 34.1 — 106.5 Accrued investment income — 16.5 4.1 — 20.6 Premiums receivable — 177.8 271.1 — 448.9 Reinsurance recoverables — 1,168.5 (149.3 ) — 1,019.2 Goodwill and other intangible assets, net — 131.3 97.4 — 228.7 Current income taxes receivable, net — 0.7 5.3 — 6.0 Deferred acquisition costs, net — 62.3 77.0 — 139.3 Ceded unearned premiums — 111.0 150.9 — 261.9 Other assets 11.0 160.9 65.2 (6.4 ) 230.7 Due (to) from affiliates (39.3 ) (3.1 ) 3.1 39.3 — Intercompany note receivable — 56.2 (56.2 ) — — Investments in subsidiaries 1,738.6 — — (1,738.6 ) — Total assets $ 1,714.0 $ 4,740.1 $ 1,795.6 $ (1,705.7 ) $ 6,544.0 Liabilities and Shareholders' Equity Reserves for losses and loss adjustment expenses $ — $ 2,139.5 $ 938.7 $ — $ 3,078.2 Unearned premiums — 477.1 419.3 — 896.4 Funds held and ceded reinsurance payable, net — 654.4 (334.1 ) — 320.3 Long-term debt 28.4 288.7 56.1 — 373.2 Deferred tax liabilities, net — 30.5 10.7 — 41.2 Accrued underwriting expenses and other liabilities 16.7 93.9 55.2 — 165.8 Total liabilities 45.1 3,684.1 1,145.9 — 4,875.1 Total shareholders' equity 1,668.9 1,056.0 649.7 (1,705.7 ) 1,668.9 Total liabilities and shareholders' equity $ 1,714.0 $ 4,740.1 $ 1,795.6 $ (1,705.7 ) $ 6,544.0 (1) (2) CONDENSED CONSOLIDATING BALANCE SHEET December 31, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Assets Investments $ 0.7 $ 2,841.5 $ 1,255.7 $ — $ 4,097.9 Cash — 49.3 31.7 — 81.0 Accrued investment income — 17.8 4.3 — 22.1 Premiums receivable — 154.6 199.0 — 353.6 Reinsurance recoverables — 1,173.6 (176.4 ) — 997.2 Goodwill and other intangible assets, net — 131.7 99.1 — 230.8 Current income taxes receivable, net — 10.1 4.8 — 14.9 Deferred acquisition costs, net — 58.0 66.6 — 124.6 Ceded unearned premiums — 98.5 109.1 — 207.6 Other assets 9.6 174.1 67.9 (25.0 ) 226.6 Due from (to) affiliates 2.9 (19.8 ) 19.8 (2.9 ) — Intercompany note receivable — 72.0 (72.0 ) — — Investments in subsidiaries 1,698.0 — — (1,698.0 ) — Total assets $ 1,711.2 $ 4,761.4 $ 1,609.6 $ (1,725.9 ) $ 6,356.3 Liabilities and Shareholders' Equity Reserves for losses and loss adjustment expenses $ — $ 2,136.4 $ 906.0 $ — $ 3,042.4 Unearned premiums — 448.9 368.3 — 817.2 Funds held and ceded reinsurance payable, net — 675.1 (441.3 ) — 233.8 Long-term debt 49.0 288.7 61.4 (20.6 ) 378.5 Deferred tax liabilities, net — 41.2 11.8 — 53.0 Accrued underwriting expenses and other liabilities 15.5 104.2 65.0 — 184.7 Total liabilities 64.5 3,694.5 971.2 (20.6 ) 4,709.6 Total shareholders' equity 1,646.7 1,066.9 638.4 (1,705.3 ) 1,646.7 Total liabilities and shareholders' equity $ 1,711.2 $ 4,761.4 $ 1,609.6 $ (1,725.9 ) $ 6,356.3 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE THREE MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 118.8 $ 227.2 $ — $ 346.0 Net investment (expense) income (0.3 ) 14.0 8.1 — 21.8 Net realized investment and other gains (loss) 2.0 7.4 (2.1 ) (2.0 ) 5.3 Total revenue 1.7 140.2 233.2 (2.0 ) 373.1 Expenses: Losses and loss adjustment expenses — 64.4 126.2 — 190.6 Underwriting, acquisition and insurance expenses 4.8 49.6 85.1 — 139.5 Interest expense 0.2 3.8 0.6 — 4.6 Fee expense (income), net — 1.6 (0.9 ) — 0.7 Foreign currency exchange loss — 0.1 2.9 — 3.0 Total expenses 5.0 119.5 213.9 — 338.4 Income (loss) before income taxes (3.3 ) 20.7 19.3 (2.0 ) 34.7 Provision for income taxes — 5.4 1.4 — 6.8 Net income (loss) before equity in earnings of subsidiaries (3.3 ) 15.3 17.9 (2.0 ) 27.9 Equity in undistributed earnings of subsidiaries 31.2 — — (31.2 ) — Net income $ 27.9 $ 15.3 $ 17.9 $ (33.2 ) $ 27.9 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE THREE MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 117.5 $ 218.6 $ — $ 336.1 Net investment (expense) income (0.1 ) 13.8 6.9 — 20.6 Net realized investment and other gains (loss) — 13.9 4.6 — 18.5 Total revenue (0.1 ) 145.2 230.1 — 375.2 Expenses: Losses and loss adjustment expenses — 68.8 116.3 — 185.1 Underwriting, acquisition and insurance expenses 4.1 50.1 82.6 — 136.8 Interest expense 0.6 3.7 0.9 (0.1 ) 5.1 Fee expense (income), net — 1.7 (1.6 ) — 0.1 Foreign currency exchange (gain) loss — (0.1 ) 3.5 — 3.4 Total expenses 4.7 124.2 201.7 (0.1 ) 330.5 Income (loss) before income taxes (4.8 ) 21.0 28.4 0.1 44.7 Provision for income taxes — 5.1 1.0 — 6.1 Net income (loss) before equity in earnings of subsidiaries (4.8 ) 15.9 27.4 0.1 38.6 Equity in undistributed earnings of subsidiaries 43.4 — — (43.4 ) — Net income $ 38.6 $ 15.9 $ 27.4 $ (43.3 ) $ 38.6 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE SIX MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 253.9 $ 426.7 $ — $ 680.6 Net investment (expense) income (0.5 ) 28.5 14.6 — 42.6 Net realized investment and other gains (loss) 2.0 23.3 (2.0 ) (2.0 ) 21.3 Total revenue 1.5 305.7 439.3 (2.0 ) 744.5 Expenses: Losses and loss adjustment expenses — 144.6 229.7 — 374.3 Underwriting, acquisition and insurance expenses 9.5 101.5 158.1 — 269.1 Interest expense 0.7 7.6 1.2 — 9.5 Fee expense (income), net — 2.4 (1.3 ) — 1.1 Foreign currency exchange loss (gain) — 0.9 (7.5 ) — (6.6 ) Total expenses 10.2 257.0 380.2 — 647.4 Income (loss) before income taxes (8.7 ) 48.7 59.1 (2.0 ) 97.1 Provision (benefit) for income taxes — 11.2 (0.8 ) — 10.4 Net income (loss) before equity in earnings of subsidiaries (8.7 ) 37.5 59.9 (2.0 ) 86.7 Equity in undistributed earnings of subsidiaries 95.4 — — (95.4 ) — Net income $ 86.7 $ 37.5 $ 59.9 $ (97.4 ) $ 86.7 ( 1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE SIX MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 229.5 $ 432.3 $ — $ 661.8 Net investment (expense) income (0.2 ) 28.8 15.3 — 43.9 Net realized investment and other gains (loss) — 25.4 4.2 — 29.6 Total revenue (0.2 ) 283.7 451.8 — 735.3 Expenses: Losses and loss adjustment expenses — 141.3 226.3 — 367.6 Underwriting, acquisition and insurance expenses 10.1 96.4 159.0 — 265.5 Interest expense 1.2 7.5 1.6 (0.2 ) 10.1 Fee expense (income), net — 3.0 (1.5 ) — 1.5 Foreign currency exchange (gain) loss — (0.2 ) 3.4 — 3.2 Total expenses 11.3 248.0 388.8 (0.2 ) 647.9 Income (loss) before income taxes (11.5 ) 35.7 63.0 0.2 87.4 Provision for income taxes — 8.1 0.5 — 8.6 Net income (loss) before equity in earnings of subsidiaries (11.5 ) 27.6 62.5 0.2 78.8 Equity in undistributed earnings of subsidiaries 90.3 — — (90.3 ) — Net income $ 78.8 $ 27.6 $ 62.5 $ (90.1 ) $ 78.8 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE SIX MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Net cash flows from operating activities $ 11.4 $ 20.7 $ 62.5 $ — $ 94.6 Cash flows from investing activities: Proceeds from sales of investments — 493.4 150.5 — 643.9 Maturities and mandatory calls of fixed maturity investments — 311.7 70.9 — 382.6 Purchases of investments — (770.6 ) (246.7 ) — (1,017.3 ) Change in short-term investments and foreign regulatory deposits 0.2 (6.9 ) (34.0 ) — (40.7 ) Settlements of foreign currency exchange forward contracts 0.8 — (5.4 ) — (4.6 ) Purchases of fixed assets and other, net 0.2 (0.4 ) 4.4 — 4.2 Cash used by investing activities 1.2 27.2 (60.3 ) — (31.9 ) Cash flows from financing activities: Borrowings under intercompany note, net — — — — — Activity under stock incentive plans (1.4 ) — — — (1.4 ) Repurchase of Company's common shares — (24.9 ) — — (24.9 ) Excess tax expense from share-based payment arrangements — 0.1 — — 0.1 Payment of cash dividend to common shareholders (11.2 ) — — — (11.2 ) Cash used by financing activities (12.6 ) (24.8 ) — — (37.4 ) Effect of exchange rate changes on cash — — 0.2 — 0.2 Change in cash — 23.1 2.4 — 25.5 Cash, beginning of the period — 49.3 31.7 — 81.0 Cash, end of period $ — $ 72.4 $ 34.1 $ — $ 106.5 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE SIX MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Net cash flows from operating activities $ (14.3 ) $ (42.2 ) $ 26.6 $ 6.4 $ (23.5 ) Cash flows from investing activities: Proceeds from sales of investments — $ 389.6 242.7 — 632.3 Maturities and mandatory calls of fixed maturity investments — $ 100.6 56.2 — 156.8 Purchases of investments — $ (481.0 ) (285.2 ) — (766.2 ) Change in short-term investments and foreign regulatory deposits 0.7 $ 24.9 24.9 — 50.5 Settlements of foreign currency exchange forward contracts (0.1 ) — 0.2 — 0.1 Issuance of intercompany note, net — $ 14.5 (41.5 ) 27.0 — Purchases of fixed assets and other, net (6.8 ) $ (5.6 ) (15.2 ) (6.4 ) (34.0 ) Cash (used) provided by investing activities (6.2 ) $ 43.0 (17.9 ) 20.6 39.5 Cash flows from financing activities: Borrowings under intercompany note, net 27.0 — — (27.0 ) — Activity under stock incentive plans 2.2 — 0.1 — 2.3 Repurchase of Company's common shares — $ (31.2 ) — — (31.2 ) Payment of cash dividend to common shareholders (8.7 ) — — — (8.7 ) Cash provided (used) by financing activities 20.5 $ (31.2 ) 0.1 (27.0 ) (37.6 ) Effect of exchange rate changes on cash — — 0.4 — 0.4 Change in cash — $ (30.4 ) 9.2 — (21.2 ) Cash, beginning of period — $ 132.1 25.3 — 157.4 Cash, end of period $ — $ 101.7 $ 34.5 $ — $ 136.2 (1) (2)

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	1. Basis of Presentation The accompanying consolidated financial statements of Argo Group International Holdings, Ltd. (“Argo Group,” “we” or the “Company”) and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. The preparation of interim 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 financial statements and reported amounts of revenues and expenses during the reporting period. The major estimates reflected in our consolidated financial statements include, but are not limited to, reserves for losses and loss adjustment expenses; reinsurance recoverables, including the reinsurance recoverables allowance for doubtful accounts; estimates of written and earned premiums; reinsurance premium receivable; fair value of investments and assessment of potential impairment; valuation of goodwill and intangibles and our deferred tax asset valuation allowance. Actual results could differ from those estimates. Certain financial information that normally is included in annual financial statements, including certain financial statement footnotes, prepared in accordance with GAAP, is not required for interim reporting purposes and has been condensed or omitted. These statements should be read in conjunction with the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission on February 27, 2015. The interim financial information as of, and for the three and six months ended, June 30, 2015 and 2014 is unaudited. However, in the opinion of management, the interim information includes all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the results presented for the interim periods. The operating results for the interim periods are not necessarily indicative of the results to be expected for the full year. All significant intercompany amounts have been eliminated in consolidation. Certain amounts in prior years’ financial statements have been reclassified to conform to the current presentation.
10% Stock Dividend	10% Stock Dividend On February 17, 2015, our Board of Directors declared a 10% stock dividend, payable on March 16, 2015, to shareholders of record at the close of business on March 2, 2015. As a result of the stock dividend, 2,554,506 additional shares were issued. Cash was paid in lieu of fractional shares of our common shares. All references to share and per share amounts in this document and related disclosures have been adjusted to reflect the stock dividend for all periods presented.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2015
Investments Debt And Equity Securities [Abstract]
Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Investments	The amortized cost, gross unrealized gains, gross unrealized losses and fair value of investments were as follows: June 30, 2015 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities USD denominated: U.S. Governments $ 183.9 $ 1.2 $ 0.1 $ 185.0 Non-U.S. Governments 84.7 0.4 0.7 84.4 Obligations of states and political subdivisions 477.1 17.3 1.6 492.8 Credit-Financial 461.7 9.7 1.8 469.6 Credit-Industrial 430.4 7.5 2.4 435.5 Credit-Utility 143.8 2.9 2.4 144.3 Structured securities: CMO/MBS-agency (1) 143.0 6.4 0.4 149.0 CMO/MBS-non agency 12.1 0.8 — 12.9 CMBS (2) 161.9 1.1 0.7 162.3 ABS (3) 245.4 1.2 0.7 245.9 Foreign denominated: Governments 175.9 1.9 13.7 164.1 Credit 239.6 3.5 24.9 218.2 Total fixed maturities 2,759.5 53.9 49.4 2,764.0 Equity securities 332.4 164.5 10.3 486.6 Other investments 501.1 10.3 2.5 508.9 Short-term investments 322.7 — — 322.7 Total investments $ 3,915.7 $ 228.7 $ 62.2 $ 4,082.2 (1) (2) (3) December 31, 2014 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Fixed maturities USD denominated: U.S. Governments $ 184.0 $ 1.3 $ 0.3 $ 185.0 Non-U.S. Governments 79.9 0.6 0.6 79.9 Obligations of states and political subdivisions 468.1 22.9 0.3 490.7 Credit-Financial 508.1 12.3 2.3 518.1 Credit-Industrial 493.7 9.4 3.5 499.6 Credit-Utility 142.7 3.2 3.9 142.0 Structured securities: CMO/MBS-agency (1) 168.0 8.0 0.7 175.3 CMO/MBS-non agency 13.2 0.8 — 14.0 CMBS (2) 178.6 1.6 0.2 180.0 ABS (3) 221.4 0.6 1.0 221.0 Foreign denominated: Governments 148.4 1.2 9.4 140.2 Credit 211.1 2.7 18.9 194.9 Total fixed maturities 2,817.2 64.6 41.1 2,840.7 Equity securities 307.3 184.1 5.1 486.3 Other investments 488.9 7.5 1.3 495.1 Short-term investments 275.8 — — 275.8 Total investments $ 3,889.2 $ 256.2 $ 47.5 $ 4,097.9 (1) (2) (3)
Schedule of Amortized Cost and Fair Values of Fixed Maturity Investments, by Contractual Maturity	The amortized cost and fair values of fixed maturity investments as of June 30, 2015, by contractual maturity, were as follows: (in millions) Amortized Cost Fair Value Due in one year or less $ 252.7 $ 245.9 Due after one year through five years 1,207.9 1,208.7 Due after five years through ten years 555.0 557.2 Thereafter 181.5 182.1 Structured securities 562.4 570.1 Total $ 2,759.5 $ 2,764.0
Schedule Of Carrying Value And Unfunded Investment Commitments Of Other Invested Assets Portfolio	Details regarding the carrying value and unfunded investment commitments of the other invested assets portfolio as of June 30, 2015 and December 31, 2014 were as follows: June 30, 2015 (in millions) Carrying Value Unfunded Commitments Investment Type Hedge funds $ 145.6 $ — Private equity 141.8 74.5 Long only funds 202.7 — Other investments 18.8 — Total other invested assets $ 508.9 $ 74.5 December 31, 2014 (in millions) Carrying Value Unfunded Commitments Investment Type Hedge funds $ 153.2 $ — Private equity 123.6 72.9 Long only funds 200.7 — Other investments 17.6 — Total other invested assets $ 495.1 $ 72.9
Schedule of Aging of Unrealized Losses on Company's Investments in Fixed Maturities, Equity Securities and Other Investments	An aging of unrealized losses on our investments in fixed maturities, equity securities, other investments and short-term investments is presented below: June 30, 2015 Less Than One Year One Year or Greater Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturities USD denominated: U.S. Governments (2) $ 17.8 $ 0.1 $ 4.1 $ — $ 21.9 $ 0.1 Non-U.S. Governments 27.6 0.6 2.7 0.1 30.3 0.7 Obligations of states and political subdivisions 80.6 1.2 9.0 0.4 89.6 1.6 Credit-Financial 203.0 1.7 10.6 0.1 213.6 1.8 Credit-Industrial 167.8 1.9 17.8 0.5 185.6 2.4 Credit-Utility 63.8 2.3 1.5 0.1 65.3 2.4 Structured securities: CMO/MBS-agency 11.1 0.1 7.9 0.3 19.0 0.4 CMBS (2) 40.2 0.7 3.6 — 43.8 0.7 ABS 88.0 0.4 10.5 0.3 98.5 0.7 Foreign denominated: Governments 127.9 13.7 — — 127.9 13.7 Credit (2) 198.6 24.9 0.9 — 199.5 24.9 Total fixed maturities 1,026.4 47.6 68.6 1.8 1,095.0 49.4 Equity securities 90.1 10.3 — — 90.1 10.3 Other investments (2.2 ) 2.5 — — (2.2 ) 2.5 Short-term investments (1) 17.8 — — — 17.8 — Total $ 1,132.1 $ 60.4 $ 68.6 $ 1.8 $ 1,200.7 $ 62.2 (1) (2) December 31, 2014 Less Than One Year One Year or Greater Total (in millions) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Fixed maturities USD denominated: U.S. Governments $ 55.0 $ 0.2 $ 15.7 $ 0.1 $ 70.7 $ 0.3 Non-U.S. Governments 36.5 0.4 5.2 0.2 41.7 0.6 Obligations of states and political subdivisions 10.4 0.1 16.6 0.2 27.0 0.3 Credit-Financial 195.7 2.2 11.1 0.1 206.8 2.3 Credit-Industrial 240.8 3.3 12.2 0.2 253.0 3.5 Credit-Utility 63.1 3.8 1.9 0.1 65.0 3.9 Structured securities: CMO/MBS-agency 10.1 0.1 19.2 0.6 29.3 0.7 CMBS 49.3 0.1 6.0 0.1 55.3 0.2 ABS 129.2 0.7 8.1 0.3 137.3 1.0 Foreign denominated: Governments 123.7 9.3 11.2 0.1 134.9 9.4 Credit 190.8 18.7 0.9 0.2 191.7 18.9 Total fixed maturities 1,104.6 38.9 108.1 2.2 1,212.7 41.1 Equity securities 53.6 5.1 — — 53.6 5.1 Other investments (0.9 ) 1.3 — — (0.9 ) 1.3 Short-term investments — — — — — — Total $ 1,157.3 $ 45.3 $ 108.1 $ 2.2 $ 1,265.4 $ 47.5
Schedule of Company's Gross Realized Investment Gains (Losses)	The following table presents our gross realized investment gains (losses) and other: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Realized gains Fixed maturities $ 3.5 $ 6.1 $ 7.6 $ 10.7 Equity securities 9.0 8.9 12.8 15.4 Other investments 9.4 10.2 30.3 22.9 Short-term investments 1.1 0.1 1.1 0.1 Gain on sale of real estate holdings and other 0.1 — 0.4 — Gross realized investment gains 23.1 25.3 52.2 49.1 Realized losses Fixed maturities (5.3 ) (4.1 ) (9.0 ) (7.6 ) Equity securities (0.4 ) — (1.1 ) (0.1 ) Other investments (10.4 ) (1.2 ) (17.5 ) (6.1 ) Short-term investments (0.3 ) (0.1 ) (1.4 ) (0.3 ) Other assets — — — (4.0 ) Other-than-temporary impairment losses on fixed maturities (0.5 ) (1.2 ) (0.9 ) (1.2 ) Other-than-temporary impairment losses on equity securities (0.9 ) (0.2 ) (1.0 ) (0.2 ) Gross realized investment and other losses (17.8 ) (6.8 ) (30.9 ) (19.5 ) Net realized investment and other gains $ 5.3 $ 18.5 $ 21.3 $ 29.6
Schedule of Realized Gains (Losses) and Changes in Unrealized Appreciation (Depreciation)	Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments are summarized as follows: (in millions) Fixed Maturities Equity Maturities Other Investments Short Term Real Estate Holdings and Other Tax Effects Total Three Months Ended June 30, 2015 Realized before impairments $ (1.8 ) $ 8.6 $ (1.0 ) $ 0.8 $ 0.1 $ (2.2 ) $ 4.5 Realized - impairments (0.5 ) (0.9 ) — — — 0.5 (0.9 ) Change in unrealized (6.0 ) (14.0 ) — 0.2 — 10.3 (9.5 ) — Three Months Ended June 30, 2014 Realized before impairments $ 2.0 $ 8.9 $ 9.0 $ — $ — $ (5.3 ) $ 14.6 Realized - impairments (1.2 ) (0.2 ) — — — 0.4 (1.0 ) Change in unrealized 13.4 18.9 1.4 — — (8.8 ) 24.9 Six Months Ended June 30, 2015 Realized before impairments $ (1.4 ) $ 11.7 $ 12.8 $ (0.3 ) $ 0.4 $ (8.4 ) $ 14.8 Realized - impairments (0.9 ) (1.0 ) — — — 0.2 (1.7 ) Change in unrealized (18.3 ) (24.9 ) 1.6 — — 13.2 (28.4 ) Six Months Ended June 30, 2014 Realized before impairments $ 3.1 $ 15.3 $ 16.8 $ (0.2 ) $ (4.0 ) $ (8.9 ) $ 22.1 Realized - impairments (1.2 ) (0.2 ) — — — 0.5 (0.9 ) Change in unrealized 22.0 15.5 1.2 — — (12.5 ) 26.2
Financial Assets Measured at Fair Value on Recurring Basis	Based on an analysis of the inputs, our financial assets measured at fair value on a recurring basis have been categorized as follows: Fair Value Measurements at Reporting Date Using (in millions) June 30, 2015 Level 1 (a) Level 2 (b) Level 3 (c) Fixed maturities USD denominated: U.S. Governments $ 185.0 $ 104.8 $ 80.2 $ — Non-U.S. Governments 84.4 — 84.4 — Obligations of states and political subdivisions 492.8 — 492.8 — Credit-Financial 469.6 — 469.6 — Credit-Industrial 435.5 — 435.5 — Credit-Utility 144.3 — 144.3 — Structured securities: CMO/MBS-agency 149.0 — 149.0 — CMO/MBS-non agency 12.9 — 12.9 — CMBS 162.3 — 162.3 — ABS 245.9 — 245.9 — Foreign denominated: Governments 164.1 — 164.1 — Credit 218.2 — 218.2 — Total fixed maturities 2,764.0 104.8 2,659.2 — Equity securities 486.6 485.8 — 0.8 Other investments 88.5 — 88.5 — Short-term investments 322.7 320.9 1.8 — $ 3,661.8 $ 911.5 $ 2,749.5 $ 0.8 (a) (b) (c) Fair Value Measurements at Reporting Date Using (in millions) December 31, 2014 Level 1 (a) Level 2 (b) Level 3 (c) Fixed maturities USD denominated: U.S. Governments $ 185.0 $ 99.2 $ 85.8 $ — Non-U.S. Governments 79.9 — 79.9 — Obligations of states and political subdivisions 490.7 — 490.7 — Credit-Financial 518.1 — 518.1 — Credit-Industrial 499.6 — 499.6 — Credit-Utility 142.0 — 142.0 — Structured securities: CMO/MBS-agency 175.3 — 175.3 — CMO/MBS-non agency 14.0 — 14.0 — CMBS 180.0 — 180.0 — ABS 221.0 — 221.0 — Foreign denominated: Governments 140.2 — 140.2 — Credit 194.9 — 194.9 — Total fixed maturities 2,840.7 99.2 2,741.5 — Equity securities 486.3 485.4 — 0.9 Other investments 97.3 — 97.3 — Short-term investments 275.8 273.9 1.9 — $ 3,700.1 $ 858.5 $ 2,840.7 $ 0.9 (a) (b) (c)
Schedule of Reconciliation of Beginning and Ending Balances for Investments Categorized as Level 3	A reconciliation of the beginning and ending balances for the investments categorized as Level 3 are as follows: Fair Value Measurements Using Observable Inputs (Level 3) (in millions) Equity Securities Total Beginning balance, January 1, 2015 $ 0.9 $ 0.9 Transfers into Level 3 — — Transfers out of Level 3 — — Total gains or losses (realized/unrealized): Included in net income (loss) — — Included in other comprehensive income (loss) — — Purchases, issuances, sales, and settlements Purchases — — Issuances — — Sales (0.1 ) (0.1 ) Settlements — Ending balance, June 30, 2015 $ 0.8 $ 0.8 Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at June 30, 2015 $ — $ — (in millions) Equity Securities Other Assets Total Beginning balance, January 1, 2014 $ 1.3 $ 2.6 $ 3.9 Transfers into Level 3 — — — Transfers out of Level 3 — — — Total gains or losses (realized/unrealized): Included in net income (loss) — — — Included in other comprehensive income (loss) 0.1 — 0.1 Purchases, issuances, sales, and settlements Purchases — — — Issuances — — — Sales (0.5 ) — (0.5 ) Settlements — (2.6 ) (2.6 ) Ending balance, December 31, 2014 $ 0.9 $ — $ 0.9 Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014 $ — $ — $ —

Reserves for Losses and Loss 25

Reserves for Losses and Loss Adjustment Expenses (Tables)	6 Months Ended
	Jun. 30, 2015
Insurance [Abstract]
Reserves for Losses and Loss Adjustment Expenses	The following table provides a reconciliation of reserves for losses and loss adjustment expenses (“LAE”): For the Six Months Ended June 30, (in millions) 2015 2014 Net reserves beginning of the year 2,137.1 $ 2,107.6 Add: Losses and LAE incurred during current calendar year, net of reinsurance: Current accident year 383.0 390.9 Prior accident years (8.7 ) (23.3 ) Losses and LAE incurred during calendar year, net of reinsurance 374.3 367.6 Deduct: Losses and LAE payments made during current calendar year, net of reinsurance: Current accident year 52.8 71.6 Prior accident years 313.3 290.3 Losses and LAE payments made during current calendar year, net of reinsurance: 366.1 361.9 Change in participation interest (1) (1.2 ) 24.7 Foreign exchange adjustments (14.5 ) 4.4 Net reserves - end of period 2,129.6 2,142.4 Add: Reinsurance recoverables on unpaid losses and LAE, end of period 948.6 925.5 Gross reserves - end of period 3,078.2 $ 3,067.9

Disclosures about Fair Value 26

Disclosures about Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Summary of Company's Financial Instruments Whose Carrying Amount Did Not Equal Fair Value	A summary of our financial instruments whose carrying value did not equal fair value is shown below: June 30, 2015 December 31, 2014 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Junior subordinated debentures $ 172.7 $ 156.6 $ 172.7 $ 155.5 Senior unsecured fixed rate notes 143.8 145.0 143.8 132.3 Other indebtedness: Floating rate loan stock 56.1 50.8 61.3 55.2 Note payable 0.6 0.6 0.7 0.6 $ 373.2 $ 353.0 $ 378.5 $ 343.6

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Schedule of Repurchase of Shares	In 2015, we repurchased shares under Securities Exchange Act of 1934 Rule 10b5-1 trading plans as follows: Date Trading Plan Initiated 2015 Purchase Period Number of Shares Repurchased Average Price of Shares Repurchased Total Cost (in millions) Repurchase Authorization Year 12/15/2014 01/05/2015-02/12/2015 117,482 $ 53.50 $ 6.3 2013 03/16/2015 03/18/2015-05/06/2015 150,050 $ 49.53 $ 7.4 2013

Accumulated Other Comprehensi28

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income (Loss)	A summary of changes in accumulated other comprehensive income (loss), net of taxes (where applicable) by component for the six months ended June 30, 2015 and 2014 is presented below: (in millions) Foreign Currency Translation Adjustments Unrealized Holding Gains on Securities Defined Benefit Pension Plans Total Balance, January 1, 2015 $ (15.6 ) $ 130.7 $ (7.0 ) $ 108.1 Other comprehensive loss before reclassifications (2.6 ) (24.3 ) — (26.9 ) Amounts reclassified from accumulated other comprehensive loss — (4.1 ) — (4.1 ) Net current-period other comprehensive loss (2.6 ) (28.4 ) — (31.0 ) Balance at June 30, 2015 $ (18.2 ) $ 102.3 $ (7.0 ) $ 77.1 (in millions) Foreign Currency Translation Adjustments Unrealized Holding Gains on Securities Defined Benefit Pension Plans Total Balance, January 1, 2014 $ (11.5 ) $ 163.9 $ (4.6 ) $ 147.8 Other comprehensive income before reclassifications 0.4 39.3 — 39.7 Amounts reclassified from accumulated other comprehensive income — (13.1 ) — (13.1 ) Net current-period other comprehensive income 0.4 26.2 — 26.6 Balance at June 30, 2014 $ (11.1 ) $ 190.1 $ (4.6 ) $ 174.4
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	The following tables illustrate the amounts reclassified from accumulated other comprehensive (loss) income shown in the above tables that have been included in our Consolidated Statements of Income: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Unrealized gains and losses on securities: Net realized investment losses $ (9.5 ) $ (16.1 ) $ (7.0 ) $ (16.2 ) Benefit for income taxes 2.8 3.0 2.9 3.1 Net of taxes $ (6.7 ) $ (13.1 ) $ (4.1 ) $ (13.1 )

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Net Income Per Common Share on Basic and Diluted Basis	The following table presents the calculation of net income per common share on a basic and diluted basis (all balances have been adjusted to reflect the 10% stock dividend): For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions, except number of shares and per share amounts) 2015 2014 2015 2014 Net income $ 27.9 $ 38.6 $ 86.7 $ 78.8 Weighted average common shares outstanding - basic 27,948,978 28,761,138 28,038,836 28,962,406 Effect of dilutive securities: Equity compensation awards 521,763 513,433 534,726 505,307 Weighted average common shares outstanding - diluted 28,470,741 29,274,571 28,573,562 29,467,713 Net income per common share: Basic $ 1.00 $ 1.34 $ 3.09 $ 2.72 Diluted $ 0.98 $ 1.32 $ 3.03 $ 2.67

Supplemental Cash Flow Inform30

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2015
Supplemental Cash Flow Elements [Abstract]
Schedule of Interest Paid	Interest paid. For the Six Months Ended June 30, (in millions) 2015 2014 Senior unsecured fixed rate notes $ 4.7 $ 4.7 Junior subordinated debentures 3.5 3.9 Other indebtedness 1.2 1.4 Total interest paid $ 9.4 $ 10.0

Share-based Compensation (Table

Share-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Fair Value Assumptions	The following table summarizes the assumptions we used for the six months ended June 30, 2015 and 2014: For the Six Months Ended June 30, 2015 2014 Risk-free rate of return 1.70% 1.64% Expected dividend yields 1.57% 1.55% Expected award life (years) 4.62 4.71 Expected volatility 21.10% 23.41%
Summary of Restricted Share Activity	A summary of restricted share activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Grant Date Fair Value Outstanding at January 1, 2015 313,716 $ 31.38 Granted 297,873 $ 39.21 Vested and issued (118,882 ) $ 26.78 Expired or forfeited (8,938 ) $ 41.76 Outstanding at June 30, 2015 483,769 $ 37.14
Summary of Stock-Settled SARs Activity	A summary of stock-settled SARs activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Exercise Price Outstanding at January 1, 2015 1,313,726 $ 28.57 Granted 243,305 $ 39.43 Exercised (78,022 ) $ 26.26 Expired or forfeited (7,231 ) $ 31.68 Outstanding at June 30, 2015 1,471,778 $ 29.67
Summary of Cash-Settled SARs Activity	A summary of cash-settled SARs activity as of June 30, 2015 and changes during the six months then ended is as follows: Shares Weighted-Average Exercise Price Outstanding at January 1, 2015 2,001,451 $ 32.76 Granted 913,157 $ 47.48 Exercised (306,278 ) $ 29.22 Expired or forfeited (91,932 ) $ 37.22 Outstanding at June 30, 2015 2,516,398 $ 38.37

Underwriting, Acquisition and32

Underwriting, Acquisition and Insurance Expenses (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Underwriting, Acquisition and Insurance Expenses	Underwriting, acquisition and insurance expenses were as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Commissions $ 67.2 $ 63.3 $ 125.9 $ 118.2 General expenses 79.7 74.1 152.6 142.9 Premium taxes, boards and bureaus — 5.7 0.6 12.3 146.9 143.1 279.1 273.4 Net deferral of policy acquisition costs (7.4 ) (6.3 ) (10.0 ) (7.9 ) Total underwriting, acquisition and insurance expenses $ 139.5 $ 136.8 $ 269.1 $ 265.5

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income Tax Provision (Benefit)	Our income tax provision includes the following components: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Current tax provision $ 9.0 $ 2.9 $ 8.8 $ 4.3 Deferred tax (benefit) provision related to: Future tax deductions (2.9 ) 3.0 2.6 33.2 Valuation allowance change 0.7 0.2 (1.0 ) (28.9 ) Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6
Schedule of Pre-Tax Income (Loss) and Effective Income Tax Rates	For the three and six months ended June 30, 2015 and 2014, pre-tax income (loss) attributable to our operations and the operations’ effective tax rates were as follows: For the Three Months Ended June 30, (in millions) 2015 2014 Pre-Tax Income (Loss) Effective Tax Rate Pre-Tax Income (Loss) Effective Tax Rate Bermuda $ 18.3 0.0 % $ 25.0 0.0 % United States 20.2 27.0 % 20.9 24.1 % United Kingdom (2.9 ) -46.9 % (5.4 ) -19.4 % Belgium 0.1 16.5 % — (1) 64.2 % Brazil (1.2 ) 0.0 % 5.1 0.0 % United Arab Emirates 0.1 0.0 % (0.1 ) 0.0 % Ireland (0.1 ) 0.0 % — (1) 0.0 % Malta 0.2 0.0 % (0.6 ) 0.0 % Switzerland — (1) -36.7 % (0.2 ) 18.2 % Pre-tax income $ 34.7 $ 44.7 For the Six Months Ended June 30, (in millions) 2015 2014 Pre-Tax Income (Loss) Effective Tax Rate Pre-Tax Income (Loss) Effective Tax Rate Bermuda $ 44.0 0.0 % 46.9 0.0 % United States 48.7 23.0 % 35.7 22.7 % United Kingdom 7.2 -12.0 % 1.9 25.4 % Belgium (0.1 ) -24.2 % — (1) 43.3 % Brazil (3.0 ) 0.0 % 5.1 0.0 % United Arab Emirates 0.1 0.0 % (1.0 ) 0.0 % Ireland (0.1 ) 0.0 % — (1) 0.0 % Malta 0.3 0.0 % (1.0 ) 0.0 % Switzerland — (1) -18.6 % (0.2 ) 21.0 % Pre-tax income $ 97.1 $ 87.4 (1)
Reconciliation of Difference Between Provision for Income Taxes and Expected Tax Provision at Weighted Average Tax Rate	A reconciliation of the difference between the provision for income taxes and the expected tax provision at the weighted average tax rate is as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Income tax provision at expected rate $ 6.2 $ 9.8 $ 17.4 $ 14.5 Tax effect of: Tax-exempt interest (1.0 ) (1.1 ) (1.9 ) (2.3 ) Dividends received deduction (0.6 ) (0.6 ) (1.2 ) (1.2 ) Valuation allowance change 0.7 0.2 (1.0 ) (28.9 ) Other permanent adjustments, net — (1.0 ) 0.2 (0.9 ) Adjustment for annualized rate 0.3 (2.6 ) (0.2 ) (1.8 ) United States state tax (benefit) expense — (0.1 ) (2.5 ) — Capital loss carryforward from prior merger — — — 29.8 Other foreign adjustments 0.4 — 0.1 — Prior period adjustments to deferred — (1.0 ) — (1.0 ) Prior year foreign taxes recovered — — (1.2 ) — Foreign exchange adjustments 0.6 2.3 0.4 0.1 Foreign withholding taxes 0.2 0.2 0.3 0.3 Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6 Income tax provision (benefit) - Foreign $ 1.4 $ 1.0 $ (0.8 ) $ 0.4 Income tax provision - United States, Federal 5.2 5.0 14.7 7.8 Income tax (benefit) provision - United States, state — (0.1 ) (3.8 ) 0.1 Foreign withholding tax - United States 0.2 0.2 0.3 0.3 Income tax provision $ 6.8 $ 6.1 $ 10.4 $ 8.6

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2015
Segment Reporting [Abstract]
Revenue and Income (Loss) Before Income Taxes for Each Segment	Revenue and income (loss) before income taxes for each segment were as follows: For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Revenue: Earned premiums Excess and Surplus Lines $ 131.1 $ 125.3 $ 254.2 $ 242.7 Commercial Specialty 71.7 71.1 144.3 142.8 International Specialty 38.3 37.6 75.6 74.6 Syndicate 1200 104.5 102.2 206.4 201.5 Run-off Lines 0.4 (0.1 ) 0.1 0.2 Total earned premiums 346.0 336.1 680.6 661.8 Net investment income Excess and Surplus Lines 9.0 9.0 17.5 18.3 Commercial Specialty 4.7 4.6 9.2 9.3 International Specialty 3.0 2.0 5.9 3.8 Syndicate 1200 2.4 2.1 4.6 5.8 Run-off Lines 2.1 2.3 4.1 4.8 Corporate and Other 0.6 0.6 1.3 1.9 Total net investment income 21.8 20.6 42.6 43.9 Net realized investment and other gains 5.3 18.5 21.3 29.6 Total revenue $ 373.1 $ 375.2 $ 744.5 $ 735.3 For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Income (loss) before income taxes Excess and Surplus Lines $ 24.2 $ 28.2 $ 48.9 $ 48.3 Commercial Specialty 4.6 (0.5 ) 8.4 1.2 International Specialty 8.8 5.6 17.9 12.4 Syndicate 1200 10.1 10.1 21.1 25.9 Run-off Lines (1.1 ) (3.4 ) 0.1 (9.3 ) Total segment income before taxes 46.6 40.0 96.4 78.5 Corporate and Other (17.2 ) (13.8 ) (20.6 ) (20.7 ) Net realized investment and other gains 5.3 18.5 21.3 29.6 Total income before income taxes $ 34.7 $ 44.7 $ 97.1 $ 87.4
Schedule of Earned Premiums by Geographic Location	The table below presents earned premiums by geographic location for the three and six months ended June 30, 2015 and 2014. For this disclosure, we determine geographic location by the country of domicile of our subsidiaries that underwrite the business and not by the location of insureds or reinsureds from whom the business was generated. For the Three Months Ended June 30, For the Six Months Ended June 30, (in millions) 2015 2014 2015 2014 Bermuda $ 26.1 $ 24.3 $ 50.0 $ 48.7 Brazil 11.9 11.8 24.4 24.4 Malta 0.4 0.6 0.9 1.1 United Kingdom 104.5 102.6 206.4 201.5 United States 203.1 196.8 398.9 386.1 Total earned premiums $ 346.0 $ 336.1 $ 680.6 $ 661.8
Identifiable Assets	The following table represents identifiable assets: June 30, December 31, (in millions) 2015 2014 Excess and Surplus Lines $ 2,411.2 $ 2,350.7 Commercial Specialty 1,358.2 1,358.5 International Specialty 836.3 776.8 Syndicate 1200 1,316.4 1,258.5 Run-off Lines 577.0 552.8 Corporate and Other 44.9 59.0 Total $ 6,544.0 $ 6,356.3

Information Provided in Conne35

Information Provided in Connection with Outstanding Debt of Subsidiaries (Tables)	6 Months Ended
	Jun. 30, 2015
Debt Disclosure [Abstract]
Condensed Consolidating Balance Sheet	CONDENSED CONSOLIDATING BALANCE SHEET JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Assets Investments $ 3.7 $ 2,785.6 $ 1,292.9 $ — $ 4,082.2 Cash — 72.4 34.1 — 106.5 Accrued investment income — 16.5 4.1 — 20.6 Premiums receivable — 177.8 271.1 — 448.9 Reinsurance recoverables — 1,168.5 (149.3 ) — 1,019.2 Goodwill and other intangible assets, net — 131.3 97.4 — 228.7 Current income taxes receivable, net — 0.7 5.3 — 6.0 Deferred acquisition costs, net — 62.3 77.0 — 139.3 Ceded unearned premiums — 111.0 150.9 — 261.9 Other assets 11.0 160.9 65.2 (6.4 ) 230.7 Due (to) from affiliates (39.3 ) (3.1 ) 3.1 39.3 — Intercompany note receivable — 56.2 (56.2 ) — — Investments in subsidiaries 1,738.6 — — (1,738.6 ) — Total assets $ 1,714.0 $ 4,740.1 $ 1,795.6 $ (1,705.7 ) $ 6,544.0 Liabilities and Shareholders' Equity Reserves for losses and loss adjustment expenses $ — $ 2,139.5 $ 938.7 $ — $ 3,078.2 Unearned premiums — 477.1 419.3 — 896.4 Funds held and ceded reinsurance payable, net — 654.4 (334.1 ) — 320.3 Long-term debt 28.4 288.7 56.1 — 373.2 Deferred tax liabilities, net — 30.5 10.7 — 41.2 Accrued underwriting expenses and other liabilities 16.7 93.9 55.2 — 165.8 Total liabilities 45.1 3,684.1 1,145.9 — 4,875.1 Total shareholders' equity 1,668.9 1,056.0 649.7 (1,705.7 ) 1,668.9 Total liabilities and shareholders' equity $ 1,714.0 $ 4,740.1 $ 1,795.6 $ (1,705.7 ) $ 6,544.0 (1) (2) CONDENSED CONSOLIDATING BALANCE SHEET December 31, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Assets Investments $ 0.7 $ 2,841.5 $ 1,255.7 $ — $ 4,097.9 Cash — 49.3 31.7 — 81.0 Accrued investment income — 17.8 4.3 — 22.1 Premiums receivable — 154.6 199.0 — 353.6 Reinsurance recoverables — 1,173.6 (176.4 ) — 997.2 Goodwill and other intangible assets, net — 131.7 99.1 — 230.8 Current income taxes receivable, net — 10.1 4.8 — 14.9 Deferred acquisition costs, net — 58.0 66.6 — 124.6 Ceded unearned premiums — 98.5 109.1 — 207.6 Other assets 9.6 174.1 67.9 (25.0 ) 226.6 Due from (to) affiliates 2.9 (19.8 ) 19.8 (2.9 ) — Intercompany note receivable — 72.0 (72.0 ) — — Investments in subsidiaries 1,698.0 — — (1,698.0 ) — Total assets $ 1,711.2 $ 4,761.4 $ 1,609.6 $ (1,725.9 ) $ 6,356.3 Liabilities and Shareholders' Equity Reserves for losses and loss adjustment expenses $ — $ 2,136.4 $ 906.0 $ — $ 3,042.4 Unearned premiums — 448.9 368.3 — 817.2 Funds held and ceded reinsurance payable, net — 675.1 (441.3 ) — 233.8 Long-term debt 49.0 288.7 61.4 (20.6 ) 378.5 Deferred tax liabilities, net — 41.2 11.8 — 53.0 Accrued underwriting expenses and other liabilities 15.5 104.2 65.0 — 184.7 Total liabilities 64.5 3,694.5 971.2 (20.6 ) 4,709.6 Total shareholders' equity 1,646.7 1,066.9 638.4 (1,705.3 ) 1,646.7 Total liabilities and shareholders' equity $ 1,711.2 $ 4,761.4 $ 1,609.6 $ (1,725.9 ) $ 6,356.3 (1) (2)
Condensed Consolidating Statement of Income	CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE THREE MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 118.8 $ 227.2 $ — $ 346.0 Net investment (expense) income (0.3 ) 14.0 8.1 — 21.8 Net realized investment and other gains (loss) 2.0 7.4 (2.1 ) (2.0 ) 5.3 Total revenue 1.7 140.2 233.2 (2.0 ) 373.1 Expenses: Losses and loss adjustment expenses — 64.4 126.2 — 190.6 Underwriting, acquisition and insurance expenses 4.8 49.6 85.1 — 139.5 Interest expense 0.2 3.8 0.6 — 4.6 Fee expense (income), net — 1.6 (0.9 ) — 0.7 Foreign currency exchange loss — 0.1 2.9 — 3.0 Total expenses 5.0 119.5 213.9 — 338.4 Income (loss) before income taxes (3.3 ) 20.7 19.3 (2.0 ) 34.7 Provision for income taxes — 5.4 1.4 — 6.8 Net income (loss) before equity in earnings of subsidiaries (3.3 ) 15.3 17.9 (2.0 ) 27.9 Equity in undistributed earnings of subsidiaries 31.2 — — (31.2 ) — Net income $ 27.9 $ 15.3 $ 17.9 $ (33.2 ) $ 27.9 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE THREE MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 117.5 $ 218.6 $ — $ 336.1 Net investment (expense) income (0.1 ) 13.8 6.9 — 20.6 Net realized investment and other gains (loss) — 13.9 4.6 — 18.5 Total revenue (0.1 ) 145.2 230.1 — 375.2 Expenses: Losses and loss adjustment expenses — 68.8 116.3 — 185.1 Underwriting, acquisition and insurance expenses 4.1 50.1 82.6 — 136.8 Interest expense 0.6 3.7 0.9 (0.1 ) 5.1 Fee expense (income), net — 1.7 (1.6 ) — 0.1 Foreign currency exchange (gain) loss — (0.1 ) 3.5 — 3.4 Total expenses 4.7 124.2 201.7 (0.1 ) 330.5 Income (loss) before income taxes (4.8 ) 21.0 28.4 0.1 44.7 Provision for income taxes — 5.1 1.0 — 6.1 Net income (loss) before equity in earnings of subsidiaries (4.8 ) 15.9 27.4 0.1 38.6 Equity in undistributed earnings of subsidiaries 43.4 — — (43.4 ) — Net income $ 38.6 $ 15.9 $ 27.4 $ (43.3 ) $ 38.6 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE SIX MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 253.9 $ 426.7 $ — $ 680.6 Net investment (expense) income (0.5 ) 28.5 14.6 — 42.6 Net realized investment and other gains (loss) 2.0 23.3 (2.0 ) (2.0 ) 21.3 Total revenue 1.5 305.7 439.3 (2.0 ) 744.5 Expenses: Losses and loss adjustment expenses — 144.6 229.7 — 374.3 Underwriting, acquisition and insurance expenses 9.5 101.5 158.1 — 269.1 Interest expense 0.7 7.6 1.2 — 9.5 Fee expense (income), net — 2.4 (1.3 ) — 1.1 Foreign currency exchange loss (gain) — 0.9 (7.5 ) — (6.6 ) Total expenses 10.2 257.0 380.2 — 647.4 Income (loss) before income taxes (8.7 ) 48.7 59.1 (2.0 ) 97.1 Provision (benefit) for income taxes — 11.2 (0.8 ) — 10.4 Net income (loss) before equity in earnings of subsidiaries (8.7 ) 37.5 59.9 (2.0 ) 86.7 Equity in undistributed earnings of subsidiaries 95.4 — — (95.4 ) — Net income $ 86.7 $ 37.5 $ 59.9 $ (97.4 ) $ 86.7 ( 1) (2) CONDENSED CONSOLIDATING STATEMENT OF INCOME FOR THE SIX MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Premiums and other revenue: Earned premiums $ — $ 229.5 $ 432.3 $ — $ 661.8 Net investment (expense) income (0.2 ) 28.8 15.3 — 43.9 Net realized investment and other gains (loss) — 25.4 4.2 — 29.6 Total revenue (0.2 ) 283.7 451.8 — 735.3 Expenses: Losses and loss adjustment expenses — 141.3 226.3 — 367.6 Underwriting, acquisition and insurance expenses 10.1 96.4 159.0 — 265.5 Interest expense 1.2 7.5 1.6 (0.2 ) 10.1 Fee expense (income), net — 3.0 (1.5 ) — 1.5 Foreign currency exchange (gain) loss — (0.2 ) 3.4 — 3.2 Total expenses 11.3 248.0 388.8 (0.2 ) 647.9 Income (loss) before income taxes (11.5 ) 35.7 63.0 0.2 87.4 Provision for income taxes — 8.1 0.5 — 8.6 Net income (loss) before equity in earnings of subsidiaries (11.5 ) 27.6 62.5 0.2 78.8 Equity in undistributed earnings of subsidiaries 90.3 — — (90.3 ) — Net income $ 78.8 $ 27.6 $ 62.5 $ (90.1 ) $ 78.8 (1) (2)
Condensed Consolidating Statement of Cash Flows	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE SIX MONTHS ENDED JUNE 30, 2015 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Net cash flows from operating activities $ 11.4 $ 20.7 $ 62.5 $ — $ 94.6 Cash flows from investing activities: Proceeds from sales of investments — 493.4 150.5 — 643.9 Maturities and mandatory calls of fixed maturity investments — 311.7 70.9 — 382.6 Purchases of investments — (770.6 ) (246.7 ) — (1,017.3 ) Change in short-term investments and foreign regulatory deposits 0.2 (6.9 ) (34.0 ) — (40.7 ) Settlements of foreign currency exchange forward contracts 0.8 — (5.4 ) — (4.6 ) Purchases of fixed assets and other, net 0.2 (0.4 ) 4.4 — 4.2 Cash used by investing activities 1.2 27.2 (60.3 ) — (31.9 ) Cash flows from financing activities: Borrowings under intercompany note, net — — — — — Activity under stock incentive plans (1.4 ) — — — (1.4 ) Repurchase of Company's common shares — (24.9 ) — — (24.9 ) Excess tax expense from share-based payment arrangements — 0.1 — — 0.1 Payment of cash dividend to common shareholders (11.2 ) — — — (11.2 ) Cash used by financing activities (12.6 ) (24.8 ) — — (37.4 ) Effect of exchange rate changes on cash — — 0.2 — 0.2 Change in cash — 23.1 2.4 — 25.5 Cash, beginning of the period — 49.3 31.7 — 81.0 Cash, end of period $ — $ 72.4 $ 34.1 $ — $ 106.5 (1) (2) CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS FOR THE SIX MONTHS ENDED JUNE 30, 2014 (in millions) Argo Group International Holdings, Ltd (Parent Guarantor) Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) Other Subsidiaries and Eliminations (1) Consolidating Adjustments (2) Total Net cash flows from operating activities $ (14.3 ) $ (42.2 ) $ 26.6 $ 6.4 $ (23.5 ) Cash flows from investing activities: Proceeds from sales of investments — $ 389.6 242.7 — 632.3 Maturities and mandatory calls of fixed maturity investments — $ 100.6 56.2 — 156.8 Purchases of investments — $ (481.0 ) (285.2 ) — (766.2 ) Change in short-term investments and foreign regulatory deposits 0.7 $ 24.9 24.9 — 50.5 Settlements of foreign currency exchange forward contracts (0.1 ) — 0.2 — 0.1 Issuance of intercompany note, net — $ 14.5 (41.5 ) 27.0 — Purchases of fixed assets and other, net (6.8 ) $ (5.6 ) (15.2 ) (6.4 ) (34.0 ) Cash (used) provided by investing activities (6.2 ) $ 43.0 (17.9 ) 20.6 39.5 Cash flows from financing activities: Borrowings under intercompany note, net 27.0 — — (27.0 ) — Activity under stock incentive plans 2.2 — 0.1 — 2.3 Repurchase of Company's common shares — $ (31.2 ) — — (31.2 ) Payment of cash dividend to common shareholders (8.7 ) — — — (8.7 ) Cash provided (used) by financing activities 20.5 $ (31.2 ) 0.1 (27.0 ) (37.6 ) Effect of exchange rate changes on cash — — 0.4 — 0.4 Change in cash — $ (30.4 ) 9.2 — (21.2 ) Cash, beginning of period — $ 132.1 25.3 — 157.4 Cash, end of period $ — $ 101.7 $ 34.5 $ — $ 136.2 (1) (2)

Investments - Additional Inform

Investments - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015USD ($)Security	Jun. 30, 2014USD ($)	Jun. 30, 2015USD ($)Security	Jun. 30, 2014USD ($)	Jun. 30, 2015CADSecurity	Dec. 31, 2014USD ($)
Schedule Of Investments [Line Items]
Fair value of the currency forward contracts	$ 800,000	$ 600,000	$ 800,000	$ 600,000
Realized gains from currency forward contracts	200,000	1,200,000	500,000	3,600,000
Realized losses from currency forward contracts	800,000	300,000	2,000,000	1,600,000
Fair value of investments, assets managed on behalf of the trade capital providers	$ 78,300,000		$ 78,300,000			$ 75,200,000
Number of securities in an unrealized loss position, total | Security	6,517		6,517		6,517
Number of securities in an unrealized loss position for less than one year | Security	2,338		2,338		2,338
Number of securities in an unrealized loss position for a period of one year or greater | Security	104		104		104
Amortized Cost	$ 3,915,700,000		$ 3,915,700,000			3,889,200,000
Fair Value	4,082,200,000		4,082,200,000			4,097,900,000
Reported loss expense reserve	32,100,000		32,100,000			43,600,000
Securities pledged to Lloyd's	213,000,000		213,000,000			217,900,000
Transfers between Level 1 and Level 2 securities	0		0
Transfers between Level 2 and Level 1 securities	0		0
Securities Pledged as Collateral [Member]
Schedule Of Investments [Line Items]
Pledged assets separately reported, securities pledged under letters of credit facilities, at amortized cost	41,600,000		41,600,000			55,000,000
Pledged assets separately reported, securities pledged under letters of credit facilities, at fair value	41,800,000		41,800,000			55,300,000
Canadian Dollar [Member]
Schedule Of Investments [Line Items]
Fair value of the currency forward contracts	3,000,000		3,000,000
Realized gains from currency forward contracts	3,600,000		11,100,000
Realized losses from currency forward contracts	2,800,000		4,800,000
Euro [Member]
Schedule Of Investments [Line Items]
Fair value of the currency forward contracts	1,000,000	200,000	1,000,000	200,000
Realized gains from currency forward contracts	6,300,000	500,000	6,300,000	600,000
Realized losses from currency forward contracts	2,400,000	500,000	2,400,000	600,000
Currency Forward Contracts [Member]
Schedule Of Investments [Line Items]
Notional amount of the currency forward contracts	7,700,000	43,000,000	7,700,000	43,000,000
Currency Forward Contracts [Member] | Canadian Dollar [Member]
Schedule Of Investments [Line Items]
Notional amount of the currency forward contracts	114,800,000		114,800,000		CAD 142,700,000
Investment Portfolio
Schedule Of Investments [Line Items]
Fair value of the currency forward contracts	200,000		200,000
Realized gains from currency forward contracts	400,000		400,000
Realized losses from currency forward contracts	1,000,000		1,000,000
Investment Portfolio | Currency Forward Contracts [Member]
Schedule Of Investments [Line Items]
Notional amount of the currency forward contracts | CAD					CAD 21,100,000
Fixed Maturities [Member]
Schedule Of Investments [Line Items]
Other-than-temporary losses	500,000	1,200,000	900,000	1,200,000
Amortized Cost	2,759,500,000		2,759,500,000			2,817,200,000
Fair Value	2,764,000,000		2,764,000,000			2,840,700,000
Equity Securities [Member]
Schedule Of Investments [Line Items]
Other-than-temporary losses	900,000	$ 200,000	1,000,000	$ 200,000
Amortized Cost	332,400,000		332,400,000			307,300,000
Fair Value	486,600,000		486,600,000			486,300,000
Deposit with Various U.S. Canadian Insurance and Other Agencies [Member] | United States [Member]
Schedule Of Investments [Line Items]
Amortized Cost	186,200,000		186,200,000
Fair Value	$ 191,600,000		$ 191,600,000
Deposit with Various U.S. Insurance and Other Agencies [Member] | United States [Member]
Schedule Of Investments [Line Items]
Amortized Cost						186,600,000
Fair Value						$ 194,200,000

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail) - shares	May. 05, 2015	Feb. 17, 2015	May. 05, 2014	Jun. 30, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Stock dividend declared		10.00%		10.00%
Additional stock issued as dividend		2,554,506
Dividends declaration date		Feb. 17, 2015
Dividends payable date		Mar. 16, 2015
Dividend payable, date of record	Jun. 1, 2015	Mar. 2, 2015	Jun. 2, 2015

Investments - Schedule of Amort

Investments - Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value of Investments (Detail) - USD ($) $ in Millions		Jun. 30, 2015		Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 3,915.7		$ 3,889.2
Gross Unrealized Gains		228.7		256.2
Gross Unrealized Losses		62.2		47.5
Fair Value		4,082.2		4,097.9
Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,759.5		2,817.2
Gross Unrealized Gains		53.9		64.6
Gross Unrealized Losses		49.4		41.1
Fair Value		2,764		2,840.7
Fixed Maturities [Member] | U.S. Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		183.9		184
Gross Unrealized Gains		1.2		1.3
Gross Unrealized Losses		0.1	[1]	0.3
Fair Value		185		185
Fixed Maturities [Member] | Non-U.S. Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		84.7		79.9
Gross Unrealized Gains		0.4		0.6
Gross Unrealized Losses		0.7		0.6
Fair Value		84.4		79.9
Fixed Maturities [Member] | Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		477.1		468.1
Gross Unrealized Gains		17.3		22.9
Gross Unrealized Losses		1.6		0.3
Fair Value		492.8		490.7
Fixed Maturities [Member] | Credit-Financial [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		461.7		508.1
Gross Unrealized Gains		9.7		12.3
Gross Unrealized Losses		1.8		2.3
Fair Value		469.6		518.1
Fixed Maturities [Member] | Credit-Industrial [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		430.4		493.7
Gross Unrealized Gains		7.5		9.4
Gross Unrealized Losses		2.4	[1]	3.5
Fair Value		435.5		499.6
Fixed Maturities [Member] | Credit-Utility [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		143.8		142.7
Gross Unrealized Gains		2.9		3.2
Gross Unrealized Losses		2.4	[1]	3.9
Fair Value		144.3		142
Fixed Maturities [Member] | CMO/MBS-Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[2]	143		168
Gross Unrealized Gains	[2]	6.4		8
Gross Unrealized Losses	[2]	0.4	[3]	0.7
Fair Value	[2]	149		175.3
Fixed Maturities [Member] | CMO/MBS-Non Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		12.1		13.2
Gross Unrealized Gains		0.8		0.8
Gross Unrealized Losses		0		0
Fair Value		12.9		14
Fixed Maturities [Member] | CMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[4]	161.9		178.6
Gross Unrealized Gains	[4]	1.1		1.6
Gross Unrealized Losses	[4]	0.7	[1]	0.2
Fair Value	[4]	162.3		180
Fixed Maturities [Member] | ABS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[5]	245.4		221.4
Gross Unrealized Gains	[5]	1.2		0.6
Gross Unrealized Losses	[5]	0.7		1
Fair Value	[5]	245.9		221
Fixed Maturities [Member] | Foreign Denominated: Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		175.9		148.4
Gross Unrealized Gains		1.9		1.2
Gross Unrealized Losses		13.7		9.4
Fair Value		164.1		140.2
Fixed Maturities [Member] | Foreign Denominated: Credit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		239.6		211.1
Gross Unrealized Gains		3.5		2.7
Gross Unrealized Losses		24.9		18.9
Fair Value		218.2		194.9
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		332.4		307.3
Gross Unrealized Gains		164.5		184.1
Gross Unrealized Losses		10.3		5.1
Fair Value		486.6		486.3
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		501.1		488.9
Gross Unrealized Gains		10.3		7.5
Gross Unrealized Losses		2.5		1.3
Fair Value		508.9		495.1
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		322.7		275.8
Gross Unrealized Gains		0		0
Gross Unrealized Losses		0		0
Fair Value		$ 322.7		$ 275.8
[1]	Unrealized losses one year or greater are less than $0.1 million.
[2]	Collateralized mortgage obligations/mortgage-backed securities (“CMO/MBS”).
[3]	Unrealized losses less than one year are less than $0.1 million.
[4]	Commercial mortgage-backed securities (“CMBS”).
[5]	Asset-backed securities (“ABS”).

Investments - Schedule of Amo39

Investments - Schedule of Amortized Cost and Fair Values of Fixed Maturity Investments, by Contractual Maturity (Detail) $ in Millions	Jun. 30, 2015USD ($)
Investments Debt And Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 252.7
Amortized Cost, Due after one year through five years	1,207.9
Amortized Cost, Due after five years through ten years	555
Amortized Cost, Thereafter	181.5
Amortized Cost, Structured securities	562.4
Amortized Cost, Total	2,759.5
Fair Value, Due in one year or less	245.9
Fair Value, Due after one year through five years	1,208.7
Fair Value, Due after five years through ten years	557.2
Fair Value, Thereafter	182.1
Fair Value, Structured securities	570.1
Fair Value, Total	$ 2,764

Investments - Schedule of Carry

Investments - Schedule of Carrying Value and Unfunded Investment Commitments of Other Invested Assets Portfolio (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Schedule Of Investments [Line Items]
Carrying Value	$ 4,082.2	$ 4,097.9	[1]
Hedge funds [Member]
Schedule Of Investments [Line Items]
Carrying Value	145.6	153.2
Unfunded Commitments	0	0
Private equity [Member]
Schedule Of Investments [Line Items]
Carrying Value	141.8	123.6
Unfunded Commitments	74.5	72.9
Long only funds [Member]
Schedule Of Investments [Line Items]
Carrying Value	202.7	200.7
Unfunded Commitments	0	0
Other Investments [Member]
Schedule Of Investments [Line Items]
Carrying Value	18.8	17.6
Unfunded Commitments	0	0
Other invested assets [Member]
Schedule Of Investments [Line Items]
Carrying Value	508.9	495.1
Unfunded Commitments	$ 74.5	$ 72.9
[1]	Derived from audited consolidated financial statements.

Investments - Schedule of Aging

Investments - Schedule of Aging of Unrealized Losses on Company's Investments in Fixed Maturities, Equity Securities and Other Investments (Detail) - USD ($) $ in Millions		Jun. 30, 2015		Dec. 31, 2014
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		$ 1,132.1		$ 1,157.3
Unrealized Losses, Less Than One Year		60.4		45.3
Fair Value, One Year or Greater		68.6		108.1
Unrealized Losses, One Year or Greater		1.8		2.2
Fair Value, Total		1,200.7		1,265.4
Gross Unrealized Losses		62.2		47.5
Fixed Maturities [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		1,026.4		1,104.6
Unrealized Losses, Less Than One Year		47.6		38.9
Fair Value, One Year or Greater		68.6		108.1
Unrealized Losses, One Year or Greater		1.8		2.2
Fair Value, Total		1,095		1,212.7
Gross Unrealized Losses		49.4		41.1
Fixed Maturities [Member] | U.S. Governments [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		17.8	[1]	55
Unrealized Losses, Less Than One Year		0.1	[1]	0.2
Fair Value, One Year or Greater		4.1	[1]	15.7
Unrealized Losses, One Year or Greater		0	[1]	0.1
Fair Value, Total		21.9	[1]	70.7
Gross Unrealized Losses		0.1	[1]	0.3
Fixed Maturities [Member] | Non-U.S. Governments [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		27.6		36.5
Unrealized Losses, Less Than One Year		0.6		0.4
Fair Value, One Year or Greater		2.7		5.2
Unrealized Losses, One Year or Greater		0.1		0.2
Fair Value, Total		30.3		41.7
Gross Unrealized Losses		0.7		0.6
Fixed Maturities [Member] | Obligations of States and Political Subdivisions [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		80.6		10.4
Unrealized Losses, Less Than One Year		1.2		0.1
Fair Value, One Year or Greater		9		16.6
Unrealized Losses, One Year or Greater		0.4		0.2
Fair Value, Total		89.6		27
Gross Unrealized Losses		1.6		0.3
Fixed Maturities [Member] | Credit-Financial [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		203		195.7
Unrealized Losses, Less Than One Year		1.7		2.2
Fair Value, One Year or Greater		10.6		11.1
Unrealized Losses, One Year or Greater		0.1		0.1
Fair Value, Total		213.6		206.8
Gross Unrealized Losses		1.8		2.3
Fixed Maturities [Member] | Credit-Industrial [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		167.8	[1]	240.8
Unrealized Losses, Less Than One Year		1.9	[1]	3.3
Fair Value, One Year or Greater		17.8	[1]	12.2
Unrealized Losses, One Year or Greater		0.5	[1]	0.2
Fair Value, Total		185.6	[1]	253
Gross Unrealized Losses		2.4	[1]	3.5
Fixed Maturities [Member] | Credit-Utility [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		63.8	[1]	63.1
Unrealized Losses, Less Than One Year		2.3	[1]	3.8
Fair Value, One Year or Greater		1.5	[1]	1.9
Unrealized Losses, One Year or Greater		0.1	[1]	0.1
Fair Value, Total		65.3	[1]	65
Gross Unrealized Losses		2.4	[1]	3.9
Fixed Maturities [Member] | CMO/MBS-Agency [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		11.1	[2]	10.1
Unrealized Losses, Less Than One Year		0.1	[2]	0.1
Fair Value, One Year or Greater		7.9	[2]	19.2
Unrealized Losses, One Year or Greater		0.3	[2]	0.6
Fair Value, Total		19	[2]	29.3
Gross Unrealized Losses	[3]	0.4	[2]	0.7
Fixed Maturities [Member] | CMBS [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		40.2	[1]	49.3
Unrealized Losses, Less Than One Year		0.7	[1]	0.1
Fair Value, One Year or Greater		3.6	[1]	6
Unrealized Losses, One Year or Greater		0	[1]	0.1
Fair Value, Total		43.8	[1]	55.3
Gross Unrealized Losses	[4]	0.7	[1]	0.2
Fixed Maturities [Member] | ABS [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		88		129.2
Unrealized Losses, Less Than One Year		0.4		0.7
Fair Value, One Year or Greater		10.5		8.1
Unrealized Losses, One Year or Greater		0.3		0.3
Fair Value, Total		98.5		137.3
Gross Unrealized Losses	[5]	0.7		1
Fixed Maturities [Member] | Foreign Denominated: Governments [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		127.9		123.7
Unrealized Losses, Less Than One Year		13.7		9.3
Fair Value, One Year or Greater		0		11.2
Unrealized Losses, One Year or Greater		0		0.1
Fair Value, Total		127.9		134.9
Gross Unrealized Losses		13.7		9.4
Fixed Maturities [Member] | Foreign Denominated: Credit [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		198.6		190.8
Unrealized Losses, Less Than One Year		24.9		18.7
Fair Value, One Year or Greater		0.9		0.9
Unrealized Losses, One Year or Greater		0		0.2
Fair Value, Total		199.5		191.7
Gross Unrealized Losses		24.9		18.9
Equity Securities [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		90.1		53.6
Unrealized Losses, Less Than One Year		10.3		5.1
Fair Value, One Year or Greater		0		0
Unrealized Losses, One Year or Greater		0		0
Fair Value, Total		90.1		53.6
Gross Unrealized Losses		10.3		5.1
Other Investments [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		(2.2)		(0.9)
Unrealized Losses, Less Than One Year		2.5		1.3
Fair Value, One Year or Greater		0		0
Unrealized Losses, One Year or Greater		0		0
Fair Value, Total		(2.2)		(0.9)
Gross Unrealized Losses		2.5		1.3
Short-Term Investments [Member]
Schedule Of Investments [Line Items]
Fair Value, Less Than One Year		17.8		0
Unrealized Losses, Less Than One Year		0		0
Fair Value, One Year or Greater		0		0
Unrealized Losses, One Year or Greater		0		0
Fair Value, Total		17.8		0
Gross Unrealized Losses		$ 0		$ 0
[1]	Unrealized losses one year or greater are less than $0.1 million.
[2]	Unrealized losses less than one year are less than $0.1 million.
[3]	Collateralized mortgage obligations/mortgage-backed securities (“CMO/MBS”).
[4]	Commercial mortgage-backed securities (“CMBS”).
[5]	Asset-backed securities (“ABS”).

Investments - Schedule of Agi42

Investments - Schedule of Aging of Unrealized Losses on Company's Investments in Fixed Maturities, Equity Securities and Other Investments (Parenthetical) (Detail) $ in Millions	Jun. 30, 2015USD ($)
Investments Debt And Equity Securities [Abstract]
Unrealized losses less than one year	$ 0.1
Unrealized losses one year or greater	$ 0.1

Investments - Schedule of Compa

Investments - Schedule of Company's Gross Realized Investment Gains (Losses) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule Of Investments [Line Items]
Gross realized investment gains and other	$ 23.1	$ 25.3	$ 52.2	$ 49.1
Gross realized investment and other losses	(17.8)	(6.8)	(30.9)	(19.5)
Net realized investment and other gains	5.3	18.5	21.3	29.6
Other Assets [Member]
Schedule Of Investments [Line Items]
Gross realized investment and other losses	0	0	0	(4)
Fixed Maturities [Member]
Schedule Of Investments [Line Items]
Gross realized investment gains and other	3.5	6.1	7.6	10.7
Gross realized investment and other losses	(5.3)	(4.1)	(9)	(7.6)
Equity Securities [Member]
Schedule Of Investments [Line Items]
Gross realized investment gains and other	9	8.9	12.8	15.4
Gross realized investment and other losses	(0.4)	0	(1.1)	(0.1)
Other Investments [Member]
Schedule Of Investments [Line Items]
Gross realized investment gains and other	9.4	10.2	30.3	22.9
Gross realized investment and other losses	(10.4)	(1.2)	(17.5)	(6.1)
Short-Term Investments [Member]
Schedule Of Investments [Line Items]
Gross realized investment gains and other	1.1	0.1	1.1	0.1
Gross realized investment and other losses	(0.3)	(0.1)	(1.4)	(0.3)
Real Estate Holdings and Other [Member]
Schedule Of Investments [Line Items]
Gross realized investment gains and other	0.1	0	0.4	0
Other-Than-Temporary Impairment Losses on Fixed Maturities [Member]
Schedule Of Investments [Line Items]
Gross realized investment and other losses	(0.5)	(1.2)	(0.9)	(1.2)
Other-Than-Temporary Impairment Losses on Equity Securities [Member]
Schedule Of Investments [Line Items]
Gross realized investment and other losses	$ (0.9)	$ (0.2)	$ (1)	$ (0.2)

Investments - Schedule of Reali

Investments - Schedule of Realized Gains (Losses) and Changes in Unrealized of Appreciation(Depreciation) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule Of Investments [Line Items]
Realized before impairments	$ 4.5	$ 14.6	$ 14.8	$ 22.1
Realized - impairments	(0.9)	(1)	(1.7)	(0.9)
Change in unrealized	(9.5)	24.9	(28.4)	26.2
Realized before impairments, Tax Effects	(2.2)	(5.3)	(8.4)	(8.9)
Realized - impairments, Tax Effects	0.5	0.4	0.2	0.5
Change in unrealized, Tax Effects	10.3	(8.8)	13.2	(12.5)
Fixed Maturities [Member]
Schedule Of Investments [Line Items]
Realized before impairments	(1.8)	2	(1.4)	3.1
Realized - impairments	(0.5)	(1.2)	(0.9)	(1.2)
Change in unrealized	(6)	13.4	(18.3)	22
Equity Securities [Member]
Schedule Of Investments [Line Items]
Realized before impairments	8.6	8.9	11.7	15.3
Realized - impairments	(0.9)	(0.2)	(1)	(0.2)
Change in unrealized	(14)	18.9	(24.9)	15.5
Other Investments [Member]
Schedule Of Investments [Line Items]
Realized before impairments	(1)	9	12.8	16.8
Realized - impairments	0	0	0	0
Change in unrealized	0	1.4	1.6	1.2
Short-Term Investments [Member]
Schedule Of Investments [Line Items]
Realized before impairments	0.8	0	(0.3)	(0.2)
Realized - impairments	0	0	0	0
Change in unrealized	0.2	0	0	0
Real Estate Holdings and Other [Member]
Schedule Of Investments [Line Items]
Realized before impairments	0.1	0	0.4	(4)
Realized - impairments	0	0	0	0
Change in unrealized	$ 0	$ 0	$ 0	$ 0

Investments - Financial Assets

Investments - Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		$ 4,082.2	$ 4,097.9
Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		3,661.8	3,700.1
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	911.5	858.5
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	2,749.5	2,840.7
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0.8	0.9
Fixed Maturities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		2,764	2,840.7
Fixed Maturities [Member] | U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		185	185
Fixed Maturities [Member] | Non-U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		84.4	79.9
Fixed Maturities [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		492.8	490.7
Fixed Maturities [Member] | Credit-Financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		469.6	518.1
Fixed Maturities [Member] | Credit-Industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		435.5	499.6
Fixed Maturities [Member] | Credit-Utility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		144.3	142
Fixed Maturities [Member] | CMO/MBS-Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[4]	149	175.3
Fixed Maturities [Member] | CMO/MBS-Non Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		12.9	14
Fixed Maturities [Member] | CMBS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[5]	162.3	180
Fixed Maturities [Member] | ABS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[6]	245.9	221
Fixed Maturities [Member] | Foreign Denominated: Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		164.1	140.2
Fixed Maturities [Member] | Foreign Denominated: Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		218.2	194.9
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		2,764	2,840.7
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		185	185
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Non-U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		84.4	79.9
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		492.8	490.7
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Credit-Financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		469.6	518.1
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Credit-Industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		435.5	499.6
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Credit-Utility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		144.3	142
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | CMO/MBS-Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		149	175.3
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | CMO/MBS-Non Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		12.9	14
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | CMBS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		162.3	180
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | ABS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		245.9	221
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Denominated: Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		164.1	140.2
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Foreign Denominated: Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		218.2	194.9
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	104.8	99.2
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	104.8	99.2
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Non-U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Credit-Financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Credit-Industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Credit-Utility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | CMO/MBS-Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | CMO/MBS-Non Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | CMBS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | ABS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Denominated: Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Denominated: Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	2,659.2	2,741.5
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	80.2	85.8
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Non-U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	84.4	79.9
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	492.8	490.7
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Credit-Financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	469.6	518.1
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Credit-Industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	435.5	499.6
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Credit-Utility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	144.3	142
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | CMO/MBS-Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	149	175.3
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | CMO/MBS-Non Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	12.9	14
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | CMBS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	162.3	180
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | ABS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	245.9	221
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Denominated: Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	164.1	140.2
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Denominated: Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	218.2	194.9
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Non-U.S. Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Credit-Financial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Credit-Industrial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Credit-Utility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | CMO/MBS-Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | CMO/MBS-Non Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | CMBS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | ABS [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Denominated: Governments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Fixed Maturities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign Denominated: Credit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		486.6	486.3
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		486.6	486.3
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	485.8	485.4
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	0	0
Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0.8	0.9
Other Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		508.9	495.1
Other Investments [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		88.5	97.3
Other Investments [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	0	0
Other Investments [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	88.5	97.3
Other Investments [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	0	0
Short-Term Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		322.7	275.8
Short-Term Investments [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value		322.7	275.8
Short-Term Investments [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[1]	320.9	273.9
Short-Term Investments [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[2]	1.8	1.9
Short-Term Investments [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	[3]	$ 0	$ 0
[1]	Quoted prices in active markets for identical assets
[2]	Significant other observable inputs
[3]	Significant unobservable inputs
[4]	Collateralized mortgage obligations/mortgage-backed securities (“CMO/MBS”).
[5]	Commercial mortgage-backed securities (“CMBS”).
[6]	Asset-backed securities (“ABS”).

Investments - Schedule of Recon

Investments - Schedule of Reconciliation of Beginning and Ending Balances for Investments Categorized as Level 3 (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 0.9	$ 3.9
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income (loss)	0	0
Included in other comprehensive income (loss)	0	0.1
Purchases	0	0
Issuances	0	0
Sales	(0.1)	(0.5)
Settlements	0	(2.6)
Ending balance	0.8	0.9
Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at end of period	0	0
Other Assets [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	0	2.6
Transfers into Level 3		0
Transfers out of Level 3		0
Included in net income (loss)		0
Included in other comprehensive income (loss)		0
Purchases		0
Issuances		0
Sales		0
Settlements		(2.6)
Ending balance		0
Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at end of period		0
Equity Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	0.9	1.3
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Included in net income (loss)	0	0
Included in other comprehensive income (loss)	0	0.1
Purchases	0	0
Issuances	0	0
Sales	(0.1)	(0.5)
Settlements	0	0
Ending balance	0.8	0.9
Amount of total gains or losses for the year included in net income (loss) attributable to the change in unrealized gains or losses relating to assets still held at end of period	$ 0	$ 0

Reserves for Losses and Loss 47

Reserves for Losses and Loss Adjustment Expenses - Reinsurance Recoverables (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Dec. 31, 2014		Jun. 30, 2014
Liability for Claims and Claims Adjustment Expense [Abstract]
Net reserves beginning of the year	$ 2,137.1	$ 2,107.6
Losses and LAE incurred during current calendar year, net of reinsurance:
Current accident year	383	390.9
Prior accident years	(8.7)	(23.3)
Losses and LAE incurred during calendar year, net of reinsurance	374.3	367.6
Losses and LAE payments made during current calendar year, net of reinsurance:
Current accident year	52.8	71.6
Prior accident years	313.3	290.3
Losses and LAE payments made during current calendar year, net of reinsurance:	366.1	361.9
Change in participation interest	(1.2)	24.7
Foreign exchange adjustments	(14.5)	4.4
Net reserves - end of period	2,129.6	2,142.4
Reinsurance recoverables on unpaid losses and LAE, end of period			$ (948.6)			$ (925.5)
Reserves for losses and loss adjustment expenses			3,078.2	$ 3,042.4	[1]	3,067.9
Net reserves - end of period	$ 2,137.1	$ 2,107.6	$ 2,129.6	$ 2,137.1		$ 2,142.4
[1]	Derived from audited consolidated financial statements.

Reserves for Losses and Loss 48

Reserves for Losses and Loss Adjustment Expenses - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	$ 8.7	$ 23.3
Excess and Surplus Lines [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	15	21.7
Commercial Specialty [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	11.6	4.9
International Specialty [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	3.7
International Specialty [Member] | Brazil [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years		0.4
Syndicate 1200 Segment [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	2.5	15.2
Run Off Lines [Member]
Schedule Of Reserves For Losses And Loss Adjustment Expenses [Line Items]
Liability for unpaid claims and claims adjustment expense, incurred claims, prior years	$ 0.9	$ 8.3

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Jul. 16, 2014	Jun. 30, 2015	Dec. 31, 2014		Mar. 07, 2014
Debt Instrument [Line Items]
Junior subordinated debentures		$ 172,700,000	$ 172,700,000	[1]
Junior subordinated debentures, Redemption Date	Apr. 29, 2015
Junior Subordinated Debentures [Member]
Debt Instrument [Line Items]
Junior subordinated debentures	$ 20,000,000
Percentage of debt securities redeemed as compare to principal amount	90.00%
Redemption received on debt securities	$ 18,200,000
Recognition of pre-tax gain	$ 2,000,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Credit agreement with major money center banks, amount					$ 175,000,000
Revolving credit facility maturity date		Mar. 7, 2018
Letter of credit facility amount		$ 0	$ 200,000
Credit Agreement [Member] | Revolving Credit Facility
Debt Instrument [Line Items]
Letter of credit facility amount		$ 17,500,000
[1]	Derived from audited consolidated financial statements.

Disclosures about Fair Value 50

Disclosures about Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Financial Instruments Owned and Pledged as Collateral [Line Items]
Premiums receivable	$ 448.9	$ 353.6	[1]
Reinsurance recoverables	1,019.2	997.2	[1]
Premiums receivable, allowance for doubtful accounts	3.8	5.2
Over 90 Days [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Premiums receivable	13.6	12.4
Reinsurance recoverables	11.3	9.9
Reinsurance recoverables, allowance for doubtful accounts	2.5	1.8
Premiums receivables, secured by collateral	0.3	0.3
Reinsurance recoverables, secured by collateral	$ 0.6	$ 0.4
[1]	Derived from audited consolidated financial statements.

Disclosures about Fair Value 51

Disclosures about Fair Value of Financial Instruments - Summary of Company's Financial Instruments Whose Carrying Amount Did Not Equal Fair Value (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Amount	$ 373.2	$ 378.5
Fair Value	353	343.6
Junior Subordinated Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Amount	172.7	172.7
Fair Value	156.6	155.5
Senior Unsecured Fixed Rate Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Amount	143.8	143.8
Fair Value	145	132.3
Other Indebtedness [Member] | Floating Rate Loan Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Amount	56.1	61.3
Fair Value	50.8	55.2
Other Indebtedness [Member] | Notes Payable [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying Amount	0.6	0.7
Fair Value	$ 0.6	$ 0.6

Shareholders Equity - Additiona

Shareholders Equity - Additional Information (Detail) - USD ($)	Aug. 04, 2015	Jun. 15, 2015	May. 05, 2015	Feb. 17, 2015	Jun. 16, 2014	May. 05, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Nov. 05, 2013
Class Of Stock [Line Items]
Dividend declared per common share			$ 0.20			$ 0.16	$ 0.20	$ 0.16	$ 0.40	$ 0.30
Dividends payable date				Mar. 16, 2015
Dividend payable, date of record			Jun. 1, 2015	Mar. 2, 2015		Jun. 2, 2015
Stock dividend declared				10.00%			10.00%		10.00%
Dividends declaration date				Feb. 17, 2015
Additional stock issued as dividend				2,554,506
Cash dividends paid - common shares, total		$ 5,600,000			$ 4,700,000
2013 Repurchase Authorization [Member]
Class Of Stock [Line Items]
Total number of shares authorized for purchase, Value							$ 67,900,000		$ 67,900,000		$ 150,000,000
Common shares repurchased on open market							136,042		489,096
Common shares repurchased on open market, total cost							$ 6,800,000		$ 24,900,000
Common shares purchased							24,700		221,564
Common shares purchased, total cost							$ 1,300,000		$ 11,200,000
Subsequent Event [Member]
Class Of Stock [Line Items]
Dividend declared per common share	$ 0.20
Dividends payable date	Sep. 15, 2015
Dividend payable, date of record	Sep. 1, 2015

Shareholders Equity - Schedule

Shareholders Equity - Schedule of Repurchase of Shares (Detail) - 6 months ended Jun. 30, 2015 - USD ($) $ / shares in Units, $ in Millions	Total
12/15/2014 [Member]
Equity Class Of Treasury Stock [Line Items]
Date Trading Plan Initiated	Dec. 15, 2014
Number of Shares Repurchased	117,482
Average Price of Shares Repurchased	$ 53.50
Common shares purchased, total cost	$ 6.3
Repurchase Authorization Year	2,013
12/15/2014 [Member] | Treasury Shares Period Start Date [Member]
Equity Class Of Treasury Stock [Line Items]
Trading Plans Purchase Period Date Range Start	01/05/2015
12/15/2014 [Member] | Treasury Shares Period End Date [Member]
Equity Class Of Treasury Stock [Line Items]
Trading Plans Purchase Period Date Range Start	02/12/2015
1/1/2022 [Member]
Equity Class Of Treasury Stock [Line Items]
Date Trading Plan Initiated	Mar. 16, 2015
Number of Shares Repurchased	150,050
Average Price of Shares Repurchased	$ 49.53
Common shares purchased, total cost	$ 7.4
Repurchase Authorization Year	2,013
1/1/2022 [Member] | Treasury Shares Period Start Date [Member]
Equity Class Of Treasury Stock [Line Items]
Trading Plans Purchase Period Date Range Start	03/18/2015
1/1/2022 [Member] | Treasury Shares Period End Date [Member]
Equity Class Of Treasury Stock [Line Items]
Trading Plans Purchase Period Date Range Start	05/06/2015

Accumulated Other Comprehensi54

Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Beginning Balance			$ 108.1	[1]	$ 147.8
Other comprehensive (loss) income before reclassifications			(26.9)		39.7
Amounts reclassified from accumulated other comprehensive loss			(4.1)		(13.1)
Other comprehensive (loss) income, net of tax	$ (9)	$ 25.5	(31)		26.6
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Ending Balance	77.1	174.4	77.1		174.4
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Beginning Balance			(15.6)		(11.5)
Other comprehensive (loss) income before reclassifications			(2.6)		0.4
Amounts reclassified from accumulated other comprehensive loss			0		0
Other comprehensive (loss) income, net of tax			(2.6)		0.4
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Ending Balance	(18.2)	(11.1)	(18.2)		(11.1)
Unrealized Holding Gains on Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Beginning Balance			130.7		163.9
Other comprehensive (loss) income before reclassifications			(24.3)		39.3
Amounts reclassified from accumulated other comprehensive loss			(4.1)		(13.1)
Other comprehensive (loss) income, net of tax			(28.4)		26.2
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Ending Balance	102.3	190.1	102.3		190.1
Defined Benefit Pension Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Beginning Balance			(7)		(4.6)
Other comprehensive (loss) income before reclassifications			0		0
Amounts reclassified from accumulated other comprehensive loss			0		0
Other comprehensive (loss) income, net of tax			0		0
Accumulated Other Comprehensive Income (Loss) Net Of Tax, Ending Balance	$ (7)	$ (4.6)	$ (7)		$ (4.6)
[1]	Derived from audited consolidated financial statements.

Accumulated Other Comprehensi55

Accumulated Other Comprehensive Income (Loss) - Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Unrealized gains and losses on securities:
Net realized investment losses	$ (9.5)	$ (16.1)	$ (7)	$ (16.2)
Benefit for income taxes	2.8	3	2.9	3.1
Net of taxes			(4.1)	(13.1)
Unrealized Holding Gains on Securities
Unrealized gains and losses on securities:
Net of taxes			(4.1)	(13.1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Holding Gains on Securities
Unrealized gains and losses on securities:
Net realized investment losses	(9.5)	(16.1)	(7)	(16.2)
Benefit for income taxes	2.8	3	2.9	3.1
Net of taxes	$ (6.7)	$ (13.1)	$ (4.1)	$ (13.1)

Net Income Per Common Share - A

Net Income Per Common Share - Additional Information (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Feb. 17, 2015	Dec. 31, 2014	[1]
Earnings Per Share [Abstract]
Stock dividend declared	10.00%		10.00%		10.00%
Treasury shares, shares	9,095,585	8,233,645	9,095,585	8,233,645		8,606,489
Antidilutive securities excluded from computation of diluted net income per share, shares	484	2,611	484	2,611
[1]	Derived from audited consolidated financial statements.

Net Income Per Common Share - N

Net Income Per Common Share - Net Income Per Common Share on Basic and Diluted Basis (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 27.9	$ 38.6	$ 86.7	$ 78.8
Weighted average common shares outstanding - basic	27,948,978	28,761,138	28,038,836	28,962,406
Effect of dilutive securities:
Equity compensation awards	521,763	513,433	534,726	505,307
Weighted average common shares outstanding - diluted	28,470,741	29,274,571	28,573,562	29,467,713
Net income per common share - basic	$ 1	$ 1.34	$ 3.09	$ 2.72
Net income per common share - diluted	$ 0.98	$ 1.32	$ 3.03	$ 2.67

Supplemental Cash Flow Inform58

Supplemental Cash Flow Information - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Income Taxes Paid Net [Abstract]
Income taxes paid	$ 10,500,000	$ 15,600,000
Income taxes recovered	$ 11,500,000	$ 0

Supplemental Cash Flow Inform59

Supplemental Cash Flow Information - Schedule of Interest Paid (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Supplemental Cash Flow [Line Items]
Total interest paid	$ 9.4	$ 10
Senior Unsecured Fixed Rate Notes [Member]
Supplemental Cash Flow [Line Items]
Total interest paid	4.7	4.7
Junior Subordinated Debentures [Member]
Supplemental Cash Flow [Line Items]
Total interest paid	3.5	3.9
Other Indebtedness [Member]
Supplemental Cash Flow [Line Items]
Total interest paid	$ 1.2	$ 1.4

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Feb. 17, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation arrangement by share-based payment award, award vesting period, years	5 years	5 years
Stock dividend declared	10.00%		10.00%
Percentage increase in number of awards outstanding due to stock dividend	10.00%
Reduction in exercise price of awards outstanding due to stock dividend	9.09%

Share-based Compensation - Fair

Share-based Compensation - Fair Value Assumptions (Detail)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free rate of return	1.70%	1.64%
Expected dividend yields	1.57%	1.55%
Expected award life (years)	4 years 7 months 13 days	4 years 8 months 16 days
Expected volatility	21.10%	23.41%

Share-Based Compensation - 2014

Share-Based Compensation - 2014 Long-Term Incentive Plan - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	May. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Nov. 30, 2007
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				5 years	5 years
Restricted Share [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense		$ 1.5	$ 0.7	$ 3	$ 1.4
Employee service share-based compensation, unrecognized compensation costs on non-vested awards		15.5		$ 15.5
Restricted Share [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				2 years
Restricted Share [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				4 years
Stock-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense		0.3	0.7	$ 1	1.3
Employee service share-based compensation, unrecognized compensation costs on non-vested awards		3.7		$ 3.7
Stock-Settled SARs Activity [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				1 year
Stock-Settled SARs Activity [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				4 years
Cash-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense		8.5	$ 5.3	$ 11.3	$ 8
Employee service share-based compensation, unrecognized compensation costs on non-vested awards		$ 17		$ 17
Cash-Settled SARs Activity [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				1 year
Cash-Settled SARs Activity [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years				4 years
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized						4,500,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant	1,460,000
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, additional number of shares authorized	2,800,000
Count of restricted shares, settle in common shares				2.75

Share-based Compensation - Summ

Share-based Compensation - Summary of Restricted Share Activity (Detail) - 6 months ended Jun. 30, 2015 - Restricted Stock Units (RSUs) [Member] - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at January 1, 2015	313,716
Granted, Shares	297,873
Vested and issued, Shares	(118,882)
Expired or forfeited, Shares	(8,938)
Shares, Outstanding at June 30, 2015	483,769
Weighted-Average Grant Date Fair Value, Outstanding at January 1, 2015	$ 31.38
Granted, Weighted-Average Grant Date Fair Value	39.21
Vested and issued, Weighted-Average Grant Date Fair Value	26.78
Expired or forfeited, Weighted-Average Grant Date Fair Value	41.76
Weighted-Average Grant Date Fair Value, Outstanding at June 30, 2015	$ 37.14

Share-based Compensation - Su64

Share-based Compensation - Summary of Stock-Settled SARs Activity (Detail) - 6 months ended Jun. 30, 2015 - Stock-Settled SARs Activity [Member] - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at January 1, 2015	1,313,726
Granted, Shares	243,305
Exercised, Shares	(78,022)
Expired or forfeited, Shares	(7,231)
Shares, Outstanding at June 30, 2015	1,471,778
Weighted-Average Exercise Price, Outstanding at January 1, 2015	$ 28.57
Granted, Weighted-Average Exercise Price	39.43
Exercised, Weighted-Average Exercise Price	26.26
Expired or forfeited, Weighted-Average Exercise Price	31.68
Weighted-Average Exercise Price, Outstanding at June 30, 2015	$ 29.67

Share-based Compensation - Su65

Share-based Compensation - Summary of Cash-Settled SARs Activity (Detail) - 6 months ended Jun. 30, 2015 - Cash-Settled SARs Activity [Member] - $ / shares	Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Outstanding at January 1, 2015	2,001,451
Granted, Shares	913,157
Exercised, Shares	(306,278)
Expired or forfeited, Shares	(91,932)
Shares, Outstanding at June 30, 2015	2,516,398
Weighted-Average Exercise Price, Outstanding at January 1, 2015	$ 32.76
Granted, Weighted-Average Exercise Price	47.48
Exercised, Weighted-Average Exercise Price	29.22
Expired or forfeited, Weighted-Average Exercise Price	37.22
Weighted-Average Exercise Price, Outstanding at June 30, 2015	$ 38.37

Underwriting, Acquisition and66

Underwriting, Acquisition and Insurance Expenses - Underwriting, Acquisition and Insurance Expenses (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Income And Expenses [Abstract]
Commissions	$ 67.2	$ 63.3	$ 125.9	$ 118.2
General expenses	79.7	74.1	152.6	142.9
Premium taxes, boards and bureaus	0	5.7	0.6	12.3
Underwriting, acquisition and insurance expenses, total	146.9	143.1	279.1	273.4
Net deferral of policy acquisition costs	(7.4)	(6.3)	(10)	(7.9)
Total underwriting, acquisition and insurance expenses	$ 139.5	$ 136.8	$ 269.1	$ 265.5

Underwriting, Acquisition and67

Underwriting, Acquisition and Insurance Expenses - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock Compensation Plan [Member]
Underwriting Acquisition And Insurance Expense [Line Items]
Expense associated with cash settled stock appreciation rights	$ 10.4	$ 6.8	$ 15.3	$ 11.1

Income Taxes - Income Tax Provi

Income Taxes - Income Tax Provision (Benefit) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Current tax provision	$ 9	$ 2.9	$ 8.8	$ 4.3
Future tax deductions	(2.9)	3	2.6	33.2
Valuation allowance change	0.7	0.2	(1)	(28.9)
Income tax provision	$ 6.8	$ 6.1	$ 10.4	$ 8.6

Income Taxes - Schedule of Pre-

Income Taxes - Schedule of Pre-Tax Income (Loss) and Effective Income Tax Rates (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015		Jun. 30, 2014
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 34.7		$ 44.7		$ 97.1		$ 87.4
Bermuda [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 18.3		$ 25		$ 44		$ 46.9
Effective Tax Rate	0.00%		0.00%		0.00%		0.00%
United States [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 20.2		$ 20.9		$ 48.7		$ 35.7
Effective Tax Rate	27.00%		24.10%		23.00%		22.70%
United Kingdom [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (2.9)		$ (5.4)		$ 7.2		$ 1.9
Effective Tax Rate	(46.90%)		(19.40%)		(12.00%)		25.40%
Belgium [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.1		$ 0	[1]	$ (0.1)		$ 0	[1]
Effective Tax Rate	16.50%		64.20%		(24.20%)		43.30%
Brazil [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (1.2)		$ 5.1		$ (3)		$ 5.1
Effective Tax Rate	0.00%		0.00%		0.00%		0.00%
United Arab Emirates [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.1		$ (0.1)		$ 0.1		$ (1)
Effective Tax Rate	0.00%		0.00%		0.00%		0.00%
Ireland [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (0.1)		$ 0	[1]	$ (0.1)		$ 0	[1]
Effective Tax Rate	0.00%		0.00%		0.00%		0.00%
Malta [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.2		$ (0.6)		$ 0.3		$ (1)
Effective Tax Rate	0.00%		0.00%		0.00%		0.00%
Switzerland [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0	[1]	$ (0.2)		$ 0	[1]	$ (0.2)
Effective Tax Rate	(36.70%)		18.20%		(18.60%)		21.00%
[1]	Pre-tax income for the respective year was less than $0.1 million.

Income Taxes - Schedule of Pr70

Income Taxes - Schedule of Pre-Tax Income (Loss) and Effective Income Tax Rates (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015		Jun. 30, 2014
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 34.7		$ 44.7		$ 97.1		$ 87.4
Belgium [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	0.1		0	[1]	(0.1)		0	[1]
Switzerland [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	0	[1]	(0.2)		0	[1]	(0.2)
Maximum [Member] | Belgium [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)			0.1				0.1
Maximum [Member] | Switzerland [Member]
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.1		$ 0.1		$ 0.1		$ 0.1
[1]	Pre-tax income for the respective year was less than $0.1 million.

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Difference Between Provision for Income Taxes and Expected Tax Provision at Weighted Average Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Income tax provision at expected rate	$ 6.2	$ 9.8	$ 17.4	$ 14.5
Tax-exempt interest	(1)	(1.1)	(1.9)	(2.3)
Dividends received deduction	(0.6)	(0.6)	(1.2)	(1.2)
Valuation allowance change	0.7	0.2	(1)	(28.9)
Other permanent adjustments, net	0	(1)	0.2	(0.9)
Adjustment for annualized rate	0.3	(2.6)	(0.2)	(1.8)
United States state tax (benefit) expense	0	(0.1)	(2.5)	0
Capital loss carryforward from prior merger	0	0	0	29.8
Other foreign adjustments	0.4	0	0.1	0
Prior period adjustments to deferred	0	(1)	0	(1)
Prior year foreign taxes recovered	0	0	(1.2)	0
Foreign exchange adjustments	0.6	2.3	0.4	0.1
Foreign withholding taxes	0.2	0.2	0.3	0.3
Income tax provision	6.8	6.1	10.4	8.6
Income tax provision (benefit) - Foreign	1.4	1	(0.8)	0.4
Income tax provision - United States, Federal	5.2	5	14.7	7.8
Income tax (benefit) provision - United States, state	0	(0.1)	(3.8)	0.1
Foreign withholding tax - United States	$ 0.2	$ 0.2	$ 0.3	$ 0.3

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Income Tax Contingency [Line Items]
Net operating losses carryback period	2 years
Capital losses carryback period	3 years
Total net deferred tax liabilities	$ 16,800,000
Net operating loss carryforward	17,300,000
Valuation allowance	24,400,000
Loss carryforwards per year	2,800,000
Unrecognized tax benefits	0	$ 0
ARIS [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforward	1,000,000
Malta [Member]
Income Tax Contingency [Line Items]
Valuation allowance	1,800,000
Decreased valuation allowance	300,000
Brazil [Member]
Income Tax Contingency [Line Items]
Valuation allowance	7,200,000
Increased valuation allowance	200,000
PXRE Reinsurance Company [Member]
Income Tax Contingency [Line Items]
Valuation allowance	15,400,000
Reduced valuation allowance	500,000
December 31, 2025 [Member]
Income Tax Contingency [Line Items]
Loss carryforwards, amounts expiring if not utilized	15,800,000
December 31, 2027 [Member]
Income Tax Contingency [Line Items]
Loss carryforwards, amounts expiring if not utilized	1,500,000
December 31, 2027 [Member] | ARIS [Member]
Income Tax Contingency [Line Items]
Loss carryforwards, amounts expiring if not utilized	200,000
December 31, 2028 [Member] | ARIS [Member]
Income Tax Contingency [Line Items]
Loss carryforwards, amounts expiring if not utilized	400,000
December 31, 2029 [Member] | ARIS [Member]
Income Tax Contingency [Line Items]
Loss carryforwards, amounts expiring if not utilized	$ 400,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Jun. 30, 2015USD ($)
Commitments And Contingencies Disclosure [Abstract]
Contractual commitments related to its limited partnership investments	$ 74.5

Segment Information - Additiona

Segment Information - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2015USD ($)Segment	Dec. 31, 2014USD ($)
Segment Reporting [Abstract]
Number of reportable segments | Segment	4
Assets associated with trade capital providers	$ 341.6	$ 315.4

Segment Information - Revenue a

Segment Information - Revenue and Income (Loss) Before Income Taxes for Each Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Earned premiums	$ 346	$ 336.1	$ 680.6	$ 661.8
Net investment income	21.8	20.6	42.6	43.9
Net realized investment and other gains	5.3	18.5	21.3	29.6
Total revenue	373.1	375.2	744.5	735.3
Income before income taxes	34.7	44.7	97.1	87.4
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Net investment income	0.6	0.6	1.3	1.9
Net realized investment and other gains	(17.2)	(13.8)	(20.6)	(20.7)
Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	46.6	40	96.4	78.5
Excess and Surplus Lines [Member]
Segment Reporting Information [Line Items]
Earned premiums	131.1	125.3	254.2	242.7
Net investment income	9	9	17.5	18.3
Excess and Surplus Lines [Member] | Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	24.2	28.2	48.9	48.3
Commercial Specialty [Member]
Segment Reporting Information [Line Items]
Earned premiums	71.7	71.1	144.3	142.8
Net investment income	4.7	4.6	9.2	9.3
Commercial Specialty [Member] | Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	4.6	(0.5)	8.4	1.2
International Specialty [Member]
Segment Reporting Information [Line Items]
Earned premiums	38.3	37.6	75.6	74.6
Net investment income	3	2	5.9	3.8
International Specialty [Member] | Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	8.8	5.6	17.9	12.4
Syndicate 1200 [Member]
Segment Reporting Information [Line Items]
Earned premiums	104.5	102.2	206.4	201.5
Net investment income	2.4	2.1	4.6	5.8
Syndicate 1200 [Member] | Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	10.1	10.1	21.1	25.9
Run Off Lines [Member]
Segment Reporting Information [Line Items]
Earned premiums	0.4	(0.1)	0.1	0.2
Net investment income	2.1	2.3	4.1	4.8
Run Off Lines [Member] | Operating Segments [Members]
Segment Reporting Information [Line Items]
Income before income taxes	$ (1.1)	$ (3.4)	$ 0.1	$ (9.3)

Segment Information - Schedule

Segment Information - Schedule of Earned Premiums by Geographic Location (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	$ 346	$ 336.1	$ 680.6	$ 661.8
Bermuda [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	26.1	24.3	50	48.7
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	11.9	11.8	24.4	24.4
Malta [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	0.4	0.6	0.9	1.1
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	104.5	102.6	206.4	201.5
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total earned premiums	$ 203.1	$ 196.8	$ 398.9	$ 386.1

Segment Information - Identifia

Segment Information - Identifiable Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	$ 6,544	$ 6,356.3	[1]
Excess and Surplus Lines [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	2,411.2	2,350.7
Commercial Specialty [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	1,358.2	1,358.5
International Specialty [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	836.3	776.8
Syndicate 1200 [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	1,316.4	1,258.5
Run Off Lines [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	577	552.8
Corporate and Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	$ 44.9	$ 59
[1]	Derived from audited consolidated financial statements.

Information Provided in Conne78

Information Provided in Connection with Outstanding Debt of Subsidiaries - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014		Jun. 30, 2014	Dec. 31, 2013
Assets
Investments		$ 4,082.2	$ 4,097.9	[1]
Cash		106.5	81	[1]	$ 136.2	$ 157.4
Accrued investment income		20.6	22.1	[1]
Premiums receivable		448.9	353.6	[1]
Reinsurance recoverables		1,019.2	997.2	[1]
Goodwill and other intangible assets, net		228.7	230.8
Current income taxes receivable, net		6	14.9	[1]
Deferred acquisition costs, net		139.3	124.6	[1]
Ceded unearned premiums		261.9	207.6	[1]
Other assets		230.7	226.6	[1]
Due from (to) affiliates		0	0
Intercompany note receivable		0	0
Investments in subsidiaries		0	0
Total assets		6,544	6,356.3	[1]
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses		3,078.2	3,042.4	[1]	3,067.9
Unearned premiums		896.4	817.2	[1]
Funds held and ceded reinsurance payable, net		320.3	233.8
Long-term debt		373.2	378.5
Deferred tax liabilities, net		41.2	53	[1]
Accrued underwriting expenses and other liabilities		165.8	184.7
Total liabilities		4,875.1	4,709.6	[1]
Total shareholders' equity		1,668.9	1,646.7	[1]
Total liabilities and shareholders' equity		6,544	6,356.3	[1]
Argo Group International Holdings, Ltd (Parent Guarantor) [Member]
Assets
Investments		3.7	0.7
Cash		0	0		0	0
Accrued investment income		0	0
Premiums receivable		0	0
Reinsurance recoverables		0	0
Goodwill and other intangible assets, net		0	0
Current income taxes receivable, net		0	0
Deferred acquisition costs, net		0	0
Ceded unearned premiums		0	0
Other assets		11	9.6
Due from (to) affiliates		(39.3)	2.9
Intercompany note receivable		0	0
Investments in subsidiaries		1,738.6	1,698
Total assets		1,714	1,711.2
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses		0	0
Unearned premiums		0	0
Funds held and ceded reinsurance payable, net		0	0
Long-term debt		28.4	49
Deferred tax liabilities, net		0	0
Accrued underwriting expenses and other liabilities		16.7	15.5
Total liabilities		45.1	64.5
Total shareholders' equity		1,668.9	1,646.7
Total liabilities and shareholders' equity		1,714	1,711.2
Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) [Member]
Assets
Investments		2,785.6	2,841.5
Cash		72.4	49.3		101.7	132.1
Accrued investment income		16.5	17.8
Premiums receivable		177.8	154.6
Reinsurance recoverables		1,168.5	1,173.6
Goodwill and other intangible assets, net		131.3	131.7
Current income taxes receivable, net		0.7	10.1
Deferred acquisition costs, net		62.3	58
Ceded unearned premiums		111	98.5
Other assets		160.9	174.1
Due from (to) affiliates		(3.1)	(19.8)
Intercompany note receivable		56.2	72
Investments in subsidiaries		0	0
Total assets		4,740.1	4,761.4
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses		2,139.5	2,136.4
Unearned premiums		477.1	448.9
Funds held and ceded reinsurance payable, net		654.4	675.1
Long-term debt		288.7	288.7
Deferred tax liabilities, net		30.5	41.2
Accrued underwriting expenses and other liabilities		93.9	104.2
Total liabilities		3,684.1	3,694.5
Total shareholders' equity		1,056	1,066.9
Total liabilities and shareholders' equity		4,740.1	4,761.4
Other Subsidiaries and Eliminations [Member]
Assets
Investments	[2]	1,292.9	1,255.7
Cash	[2]	34.1	31.7		34.5	25.3
Accrued investment income	[2]	4.1	4.3
Premiums receivable	[2]	271.1	199
Reinsurance recoverables	[2]	(149.3)	(176.4)
Goodwill and other intangible assets, net	[2]	97.4	99.1
Current income taxes receivable, net	[2]	5.3	4.8
Deferred acquisition costs, net	[2]	77	66.6
Ceded unearned premiums	[2]	150.9	109.1
Other assets	[2]	65.2	67.9
Due from (to) affiliates	[2]	3.1	19.8
Intercompany note receivable	[2]	(56.2)	(72)
Investments in subsidiaries	[2]	0	0
Total assets	[2]	1,795.6	1,609.6
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses	[2]	938.7	906
Unearned premiums	[2]	419.3	368.3
Funds held and ceded reinsurance payable, net	[2]	(334.1)	(441.3)
Long-term debt	[2]	56.1	61.4
Deferred tax liabilities, net	[2]	10.7	11.8
Accrued underwriting expenses and other liabilities	[2]	55.2	65
Total liabilities	[2]	1,145.9	971.2
Total shareholders' equity	[2]	649.7	638.4
Total liabilities and shareholders' equity	[2]	1,795.6	1,609.6
Consolidating Adjustments [Member]
Assets
Investments	[3]	0	0
Cash	[3]	0	0		$ 0	$ 0
Accrued investment income	[3]	0	0
Premiums receivable	[3]	0	0
Reinsurance recoverables	[3]	0	0
Goodwill and other intangible assets, net	[3]	0	0
Current income taxes receivable, net	[3]	0	0
Deferred acquisition costs, net	[3]	0	0
Ceded unearned premiums	[3]	0	0
Other assets	[3]	(6.4)	(25)
Due from (to) affiliates	[3]	39.3	(2.9)
Intercompany note receivable	[3]	0	0
Investments in subsidiaries	[3]	(1,738.6)	(1,698)
Total assets	[3]	(1,705.7)	(1,725.9)
Liabilities and Shareholders' Equity
Reserves for losses and loss adjustment expenses	[3]	0	0
Unearned premiums	[3]	0	0
Funds held and ceded reinsurance payable, net	[3]	0	0
Long-term debt	[3]	0	(20.6)
Deferred tax liabilities, net	[3]	0	0
Accrued underwriting expenses and other liabilities	[3]	0	0
Total liabilities	[3]	0	(20.6)
Total shareholders' equity	[3]	(1,705.7)	(1,705.3)
Total liabilities and shareholders' equity	[3]	$ (1,705.7)	$ (1,725.9)
[1]	Derived from audited consolidated financial statements.
[2]	Includes all other subsidiaries of Argo Group International Holdings, Ltd. and all intercompany eliminations.
[3]	Includes all Argo Group parent company eliminations.

Information Provided in Conne79

Information Provided in Connection with Outstanding Debt of Subsidiaries - Condensed Consolidating Statement of Income (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Premiums and other revenue:
Earned premiums		$ 346	$ 336.1	$ 680.6	$ 661.8
Net investment (expense) income		21.8	20.6	42.6	43.9
Net realized investment and other gains (loss)		5.3	18.5	21.3	29.6
Total revenue		373.1	375.2	744.5	735.3
Expenses:
Losses and loss adjustment expenses		190.6	185.1	374.3	367.6
Underwriting, acquisition and insurance expenses		139.5	136.8	269.1	265.5
Interest expense		4.6	5.1	9.5	10.1
Fee expense, net		0.7	0.1	1.1	1.5
Foreign currency exchange loss (gain)		3	3.4	(6.6)	3.2
Total expenses		338.4	330.5	647.4	647.9
Income before income taxes		34.7	44.7	97.1	87.4
Provision for income taxes		6.8	6.1	10.4	8.6
Net income (loss) before equity in earnings of subsidiaries		27.9	38.6	86.7	78.8
Equity in undistributed earnings of subsidiaries		0	0	0	0
Net income		27.9	38.6	86.7	78.8
Argo Group International Holdings, Ltd (Parent Guarantor) [Member]
Premiums and other revenue:
Earned premiums		0	0	0	0
Net investment (expense) income		(0.3)	(0.1)	(0.5)	(0.2)
Net realized investment and other gains (loss)		2	0	2	0
Total revenue		1.7	(0.1)	1.5	(0.2)
Expenses:
Losses and loss adjustment expenses		0	0	0	0
Underwriting, acquisition and insurance expenses		4.8	4.1	9.5	10.1
Interest expense		0.2	0.6	0.7	1.2
Fee expense, net		0	0	0	0
Foreign currency exchange loss (gain)		0	0	0	0
Total expenses		5	4.7	10.2	11.3
Income before income taxes		(3.3)	(4.8)	(8.7)	(11.5)
Provision for income taxes		0	0	0	0
Net income (loss) before equity in earnings of subsidiaries		(3.3)	(4.8)	(8.7)	(11.5)
Equity in undistributed earnings of subsidiaries		31.2	43.4	95.4	90.3
Net income		27.9	38.6	86.7	78.8
Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) [Member]
Premiums and other revenue:
Earned premiums		118.8	117.5	253.9	229.5
Net investment (expense) income		14	13.8	28.5	28.8
Net realized investment and other gains (loss)		7.4	13.9	23.3	25.4
Total revenue		140.2	145.2	305.7	283.7
Expenses:
Losses and loss adjustment expenses		64.4	68.8	144.6	141.3
Underwriting, acquisition and insurance expenses		49.6	50.1	101.5	96.4
Interest expense		3.8	3.7	7.6	7.5
Fee expense, net		1.6	1.7	2.4	3
Foreign currency exchange loss (gain)		0.1	(0.1)	0.9	(0.2)
Total expenses		119.5	124.2	257	248
Income before income taxes		20.7	21	48.7	35.7
Provision for income taxes		5.4	5.1	11.2	8.1
Net income (loss) before equity in earnings of subsidiaries		15.3	15.9	37.5	27.6
Equity in undistributed earnings of subsidiaries		0	0	0	0
Net income		15.3	15.9	37.5	27.6
Other Subsidiaries and Eliminations [Member]
Premiums and other revenue:
Earned premiums	[1]	227.2	218.6	426.7	432.3
Net investment (expense) income	[1]	8.1	6.9	14.6	15.3
Net realized investment and other gains (loss)	[1]	(2.1)	4.6	(2)	4.2
Total revenue	[1]	233.2	230.1	439.3	451.8
Expenses:
Losses and loss adjustment expenses	[1]	126.2	116.3	229.7	226.3
Underwriting, acquisition and insurance expenses	[1]	85.1	82.6	158.1	159
Interest expense	[1]	0.6	0.9	1.2	1.6
Fee expense, net	[1]	(0.9)	(1.6)	(1.3)	(1.5)
Foreign currency exchange loss (gain)	[1]	2.9	3.5	(7.5)	3.4
Total expenses	[1]	213.9	201.7	380.2	388.8
Income before income taxes	[1]	19.3	28.4	59.1	63
Provision for income taxes	[1]	1.4	1	(0.8)	0.5
Net income (loss) before equity in earnings of subsidiaries	[1]	17.9	27.4	59.9	62.5
Equity in undistributed earnings of subsidiaries	[1]	0	0	0	0
Net income	[1]	17.9	27.4	59.9	62.5
Consolidating Adjustments [Member]
Premiums and other revenue:
Earned premiums	[2]	0	0	0	0
Net investment (expense) income	[2]	0	0	0	0
Net realized investment and other gains (loss)	[2]	(2)	0	(2)	0
Total revenue	[2]	(2)	0	(2)	0
Expenses:
Losses and loss adjustment expenses	[2]	0	0	0	0
Underwriting, acquisition and insurance expenses	[2]	0	0	0	0
Interest expense	[2]	0	(0.1)	0	(0.2)
Fee expense, net	[2]	0	0	0	0
Foreign currency exchange loss (gain)	[2]	0	0	0	0
Total expenses	[2]	0	(0.1)	0	(0.2)
Income before income taxes	[2]	(2)	0.1	(2)	0.2
Provision for income taxes	[2]	0	0	0	0
Net income (loss) before equity in earnings of subsidiaries	[2]	(2)	0.1	(2)	0.2
Equity in undistributed earnings of subsidiaries	[2]	(31.2)	(43.4)	(95.4)	(90.3)
Net income	[2]	$ (33.2)	$ (43.3)	$ (97.4)	$ (90.1)
[1]	Includes all other subsidiaries of Argo Group International Holdings, Ltd. and all intercompany eliminations.
[2]	Includes all Argo Group parent company eliminations.

Information Provided in Conne80

Information Provided in Connection with Outstanding Debt of Subsidiaries - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014
Condensed Financial Statements Captions [Line Items]
Net cash flows from operating activities		$ 94.6		$ (23.5)
Cash flows from investing activities:
Proceeds from sales of investments		643.9		632.3
Maturities and mandatory calls of fixed maturity investments		382.6		156.8
Purchases of investments		(1,017.3)		(766.2)
Change in short-term investments and foreign regulatory deposits		(40.7)		50.5
Settlements of foreign currency exchange forward contracts		(4.6)		0.1
Issuance of intercompany note, net				0
Purchases of fixed assets and other, net		4.2		(34)
Cash (used) provided by investing activities		(31.9)		39.5
Cash flows from financing activities:
Borrowings under intercompany note, net		0		0
Activity under stock incentive plans		(1.4)		2.3
Repurchase of Company's common shares		(24.9)		(31.2)
Excess tax expense from share-based payment arrangements		0.1		0
Payment of cash dividends to common shareholders		(11.2)		(8.7)
Cash used by financing activities		(37.4)		(37.6)
Effect of exchange rate changes on cash		0.2		0.4
Change in cash		25.5		(21.2)
Cash, beginning of period		81	[1]	157.4
Cash, end of period		106.5		136.2
Argo Group International Holdings, Ltd (Parent Guarantor) [Member]
Condensed Financial Statements Captions [Line Items]
Net cash flows from operating activities		11.4		(14.3)
Cash flows from investing activities:
Proceeds from sales of investments		0		0
Maturities and mandatory calls of fixed maturity investments		0		0
Purchases of investments		0		0
Change in short-term investments and foreign regulatory deposits		0.2		0.7
Settlements of foreign currency exchange forward contracts		0.8		(0.1)
Issuance of intercompany note, net				0
Purchases of fixed assets and other, net		0.2		(6.8)
Cash (used) provided by investing activities		1.2		(6.2)
Cash flows from financing activities:
Borrowings under intercompany note, net		0		27
Activity under stock incentive plans		(1.4)		2.2
Repurchase of Company's common shares		0		0
Excess tax expense from share-based payment arrangements		0
Payment of cash dividends to common shareholders		(11.2)		(8.7)
Cash used by financing activities		(12.6)		20.5
Effect of exchange rate changes on cash		0		0
Change in cash		0		0
Cash, beginning of period		0		0
Cash, end of period		0		0
Argo Group US, Inc. and Subsidiaries (Subsidiary Issuer) [Member]
Condensed Financial Statements Captions [Line Items]
Net cash flows from operating activities		20.7		(42.2)
Cash flows from investing activities:
Proceeds from sales of investments		493.4		389.6
Maturities and mandatory calls of fixed maturity investments		311.7		100.6
Purchases of investments		(770.6)		(481)
Change in short-term investments and foreign regulatory deposits		(6.9)		24.9
Settlements of foreign currency exchange forward contracts		0		0
Issuance of intercompany note, net				14.5
Purchases of fixed assets and other, net		(0.4)		(5.6)
Cash (used) provided by investing activities		27.2		43
Cash flows from financing activities:
Borrowings under intercompany note, net		0		0
Activity under stock incentive plans		0		0
Repurchase of Company's common shares		(24.9)		(31.2)
Excess tax expense from share-based payment arrangements		0.1
Payment of cash dividends to common shareholders		0		0
Cash used by financing activities		(24.8)		(31.2)
Effect of exchange rate changes on cash		0		0
Change in cash		23.1		(30.4)
Cash, beginning of period		49.3		132.1
Cash, end of period		72.4		101.7
Other Subsidiaries and Eliminations [Member]
Condensed Financial Statements Captions [Line Items]
Net cash flows from operating activities	[2]	62.5		26.6
Cash flows from investing activities:
Proceeds from sales of investments	[2]	150.5		242.7
Maturities and mandatory calls of fixed maturity investments	[2]	70.9		56.2
Purchases of investments	[2]	(246.7)		(285.2)
Change in short-term investments and foreign regulatory deposits	[2]	(34)		24.9
Settlements of foreign currency exchange forward contracts	[2]	(5.4)		0.2
Issuance of intercompany note, net	[2]			(41.5)
Purchases of fixed assets and other, net	[2]	4.4		(15.2)
Cash (used) provided by investing activities	[2]	(60.3)		(17.9)
Cash flows from financing activities:
Borrowings under intercompany note, net	[2]	0		0
Activity under stock incentive plans	[2]	0		0.1
Repurchase of Company's common shares	[2]	0		0
Excess tax expense from share-based payment arrangements	[2]	0
Payment of cash dividends to common shareholders	[2]	0		0
Cash used by financing activities	[2]	0		0.1
Effect of exchange rate changes on cash	[2]	0.2		0.4
Change in cash	[2]	2.4		9.2
Cash, beginning of period	[2]	31.7		25.3
Cash, end of period	[2]	34.1		34.5
Consolidating Adjustments [Member]
Condensed Financial Statements Captions [Line Items]
Net cash flows from operating activities	[3]	0		6.4
Cash flows from investing activities:
Proceeds from sales of investments	[3]	0		0
Maturities and mandatory calls of fixed maturity investments	[3]	0		0
Purchases of investments	[3]	0		0
Change in short-term investments and foreign regulatory deposits	[3]	0		0
Settlements of foreign currency exchange forward contracts	[3]	0		0
Issuance of intercompany note, net	[3]			27
Purchases of fixed assets and other, net	[3]	0		(6.4)
Cash (used) provided by investing activities	[3]	0		20.6
Cash flows from financing activities:
Borrowings under intercompany note, net	[3]	0		(27)
Activity under stock incentive plans	[3]	0		0
Repurchase of Company's common shares	[3]	0		0
Excess tax expense from share-based payment arrangements	[3]	0
Payment of cash dividends to common shareholders	[3]	0		0
Cash used by financing activities	[3]	0		(27)
Effect of exchange rate changes on cash	[3]	0		0
Change in cash	[3]	0		0
Cash, beginning of period	[3]	0		0
Cash, end of period	[3]	$ 0		$ 0
[1]	Derived from audited consolidated financial statements.
[2]	Includes all other subsidiaries of Argo Group International Holdings, Ltd. and all intercompany eliminations.
[3]	Includes all Argo Group parent company eliminations.