Consolidated Statements of Earnings and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Revenues
Net premiums earned	$ 1,017,171	$ 1,053,997
Net investment income	113,382	110,583
Net realized capital gains	43,151	96,836
Other than temporary impairment losses	(52,281)	(5,220)
Other income	36,200	30,446
Total revenues	1,157,623	1,286,642
Costs and Expenses
Net loss and loss adjustment expenses	546,916	611,159
Commissions, brokerage and other underwriting expenses	343,609	324,236
Other operating expenses	67,405	53,342
Corporate administration	12,678	9,632
Amortization of intangible assets	(1,660)	(1,861)
Interest expense	23,092	21,811
Total costs and expenses	992,040	1,018,319
Earnings before income taxes	165,583	268,323
Income taxes	40,163	63,682
Net earnings	125,420	204,641
Net earnings (losses) attributable to noncontrolling interest	211	(239)
Net earnings attributable to Alleghany stockholders	125,209	204,880
Net earnings	125,420	204,641
Other comprehensive income:
Change in unrealized gains, net of deferred taxes of $33,141 and $81,364 for 2015 and 2014, respectively	61,548	151,104
Less: reclassification for net realized capital gains and other than temporary impairment losses, net of taxes of $3,196 and ($32,066) for 2015 and 2014, respectively	5,935	(59,550)
Change in unrealized currency translation adjustment, net of deferred taxes of ($5,791)and $233 for 2015 and 2014, respectively	(10,755)	432
Retirement plans	(522)	133
Comprehensive income	181,626	296,760
Comprehensive income (losses) attributable to noncontrolling interest	211	(239)
Comprehensive income attributable to Alleghany stockholders	$ 181,415	$ 296,999
Basic earnings per share attributable to Alleghany stockholders	$ 7.82	$ 12.28
Diluted earnings per share attributable to Alleghany stockholders	$ 7.82	$ 12.28