Consolidated Statements of Earnings and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Net premiums earned	$ 1,221,565	$ 1,017,171
Net investment income	104,863	113,382
Net realized capital gains	35,893	43,151
Other than temporary impairment losses	(20,759)	(52,281)
Other revenue	137,388	36,200
Total revenues	1,478,950	1,157,623
Costs and Expenses
Net loss and loss adjustment expenses	664,644	546,916
Commissions, brokerage and other underwriting expenses	406,733	343,609
Other operating expenses	162,164	67,405
Corporate administration	9,734	12,678
Amortization of intangible assets	3,085	(1,660)
Interest expense	20,269	23,092
Total costs and expenses	1,266,629	992,040
Earnings (losses) before income taxes	212,321	165,583
Income taxes	57,668	40,163
Net earnings	154,653	125,420
Net earnings attributable to noncontrolling interest	148	211
Net earnings attributable to Alleghany stockholders	154,505	125,209
Net earnings	154,653	125,420
Other comprehensive income:
Change in unrealized gains, net of deferred taxes of $54,981 and $33,141 for 2016 and 2015, respectively	102,107	61,548
Less: reclassification for net realized capital gains and other than temporary impairment losses, net of taxes of ($5,297) and $3,196 for 2016 and 2015, respectively	(9,837)	5,935
Change in unrealized currency translation adjustment, net of deferred taxes of $11,077 and ($5,791) for 2016 and 2015, respectively	20,571	(10,755)
Retirement plans	262	(522)
Comprehensive income	267,756	181,626
Comprehensive income attributable to noncontrolling interest	148	211
Comprehensive income attributable to Alleghany stockholders	$ 267,608	$ 181,415
Basic earnings per share attributable to Alleghany stockholders	$ 10.00	$ 7.82
Diluted earnings per share attributable to Alleghany stockholders	$ 9.96	$ 7.82