Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2017		Dec. 31, 2016
Available-for-sale securities at fair value:
Equity securities (cost: 2017 - $3,170,673; 2016 - $2,816,572)		$ 4,099,467		$ 3,109,523
Debt securities (amortized cost: 2017 - $12,536,772; 2016 - $12,927,103)		12,721,399		12,983,213
Short-term investments		578,054		778,410
Marketable Securities, Total		17,398,920		16,871,146
Other invested assets		743,358		645,245
Total investments		18,800,642		18,111,269
Cash		838,375		594,091
Accrued investment income		105,877		113,763
Premium balances receivable		797,346		743,692
Reinsurance recoverables		1,746,488		1,272,219
Ceded unearned premiums		190,252		201,023
Deferred acquisition costs		453,346		448,634
Property and equipment at cost, net of accumulated depreciation and amortization		125,337		112,920
Goodwill	[1]	334,905		284,974
Intangible assets, net of amortization	[1]	459,037		378,680
Current taxes receivable		31,085		25,950
Net deferred tax assets		136,489		354,852
Funds held under reinsurance agreements		706,042		591,602
Other assets		659,096		522,922
Total assets		25,384,317		23,756,591
Liabilities, Redeemable Noncontrolling Interests and Stockholders' Equity
Loss and loss adjustment expenses		11,871,250	[2]	11,087,199
Unearned premiums		2,182,294		2,175,498
Senior Notes and other debt		1,484,897		1,476,489
Reinsurance payable		156,376		90,659
Other liabilities		1,068,907		912,081
Total liabilities		16,763,724		15,741,926
Redeemable noncontrolling interests		106,530		74,720
Common stock (shares authorized: 2017 and 2016 - 22,000,000; shares issued: 2017 and 2016 - 17,459,961)		17,460		17,460
Contributed capital		3,612,109		3,611,993
Accumulated other comprehensive income		618,118		109,284
Treasury stock, at cost (2017 - 2,069,461 shares; 2016 - 2,049,797 shares)		(824,906)		(812,840)
Retained earnings		5,091,282		5,014,048
Total stockholders' equity attributable to Alleghany stockholders		8,514,063		7,939,945
Total liabilities, redeemable noncontrolling interest and stockholders' equity		25,384,317		23,756,591
Commercial Mortgage Loan Portfolio
Available-for-sale securities at fair value:
Commercial mortgage loans		$ 658,364		$ 594,878

[1] Goodwill and intangible assets have been reduced by amounts written-down in prior periods.

[2] Includes unallocated LAE, which aggregate to 1.3 percent of gross loss and LAE reserves as of December 31, 2017. Net loss and LAE Reserves by component are shown in the preceding tables, and consolidated gross loss and LAE reserves is presented in the Consolidated Balance Sheets.