Consolidated Statements of Earnings and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues
Net premiums earned	$ 1,074,723	$ 1,098,944	$ 2,091,894	$ 2,152,941
Net investment income	103,087	114,094	216,469	224,677
Net realized capital gains	86,160	41,524	129,311	138,360
Other than temporary impairment losses	(7,317)	(932)	(59,598)	(6,152)
Other income	43,785	37,586	79,985	68,032
Total revenues	1,300,438	1,291,216	2,458,061	2,577,858
Costs and Expenses
Net loss and loss adjustment expenses	595,455	629,213	1,142,371	1,240,372
Commissions, brokerage and other underwriting expenses	363,954	359,604	707,563	683,840
Other operating expenses	63,812	66,236	131,217	119,578
Corporate administration	9,841	12,687	22,519	22,319
Amortization of intangible assets	(1,051)	(876)	(2,711)	(2,737)
Interest expense	23,375	21,932	46,467	43,743
Total costs and expenses	1,055,386	1,088,796	2,047,426	2,107,115
Earnings (losses) before income taxes	245,052	202,420	410,635	470,743
Income taxes	61,905	53,186	102,068	116,868
Net earnings	183,147	149,234	308,567	353,875
Net earnings attributable to noncontrolling interest	669	254	880	15
Net earnings attributable to Alleghany stockholders	182,478	148,980	307,687	353,860
Net earnings	183,147	149,234	308,567	353,875
Other comprehensive income:
Change in unrealized gains, net of deferred taxes of ($25,730) and $192,340 for 2015 and 2014, respectively	(109,332)	206,098	(47,785)	357,203
Less: reclassification for net realized capital gains and other than temporary impairment losses, net of taxes of ($24,400) and ($46,273) for 2015 and 2014, respectively	(51,248)	(26,385)	(45,313)	(85,935)
Change in unrealized currency translation adjustment, net of deferred taxes of $1,555 and $3,126 for 2015 and 2014, respectively	2,888	5,805	(7,867)	6,237
Retirement plans	137	(7)	(385)	126
Comprehensive income	25,592	334,745	207,217	631,506
Comprehensive income (losses) attributable to noncontrolling interest	669	254	880	15
Comprehensive income attributable to Alleghany stockholders	$ 24,923	$ 334,491	$ 206,337	$ 631,491
Basic earnings per share attributable to Alleghany stockholders	$ 11.41	$ 9.06	$ 19.22	$ 21.36
Diluted earnings per share attributable to Alleghany stockholders	$ 11.40	$ 9.06	$ 19.22	$ 21.36