Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Available-for-sale securities at fair value:
Equity securities (cost: 2014 - $2,480,172; 2013 - $1,804,698)	$ 2,895,272	$ 2,229,453
Debt securities (amortized cost: 2014 - $14,556,802; 2013 - $14,875,750)	14,766,235	14,802,890
Short-term investments	791,961	1,317,895
Marketable Securities, Total	18,453,468	18,350,238
Other invested assets	701,875	641,924
Total investments	19,155,343	18,992,162
Cash	607,605	498,315
Accrued investment income	137,658	146,381
Premium balances receivable	731,542	675,255
Reinsurance recoverables	1,370,942	1,363,707
Ceded unearned premiums	207,736	173,148
Deferred acquisition costs	378,662	334,740
Property and equipment at cost, net of accumulated depreciation and amortization	86,646	58,974
Goodwill	99,897	99,747
Intangible assets, net of amortization	131,307	127,284
Current taxes receivable	84,206	13,049
Net deferred tax assets	373,436	469,787
Other assets	564,486	408,539
Total assets	23,929,466	23,361,088
Liabilities and Stockholders' Equity
Loss and loss adjustment expenses	11,707,093	11,952,541
Unearned premiums	1,974,924	1,765,550
Senior Notes	2,079,170	1,794,407
Reinsurance payable	95,061	90,562
Other liabilities	658,751	810,507
Total liabilities	16,514,999	16,413,567
Common stock (shares authorized: 2014 and 2013 - 22,000,000; shares issued: 2014 -17,459,961; 2013 - 17,459,961)	17,460	17,460
Contributed capital	3,611,519	3,613,151
Accumulated other comprehensive income	346,030	186,930
Treasury stock, at cost (2014 - 1,223,100 shares; 2013 - 693,769 shares)	(429,666)	(213,911)
Retained earnings	3,860,302	3,320,127
Total stockholders' equity attributable to Alleghany stockholders	7,405,645	6,923,757
Noncontrolling interest	8,822	23,764
Total stockholders' equity	7,414,467	6,947,521
Total liabilities and stockholders' equity	$ 23,929,466	$ 23,361,088