Consolidated Statement of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
REVENUE
Net earned premium	$ 600,563us-gaap_PremiumsEarnedNet	$ 562,612us-gaap_PremiumsEarnedNet
Net investment income	53,482us-gaap_InvestmentIncomeNet	56,806us-gaap_InvestmentIncomeNet
Other operating income	9,219us-gaap_OtherIncome	9,266us-gaap_OtherIncome
Net realized investment gain	13,186us-gaap_RealizedInvestmentGainsLosses	20,246us-gaap_RealizedInvestmentGainsLosses
Total revenue	676,450us-gaap_Revenues	648,930us-gaap_Revenues
EXPENSE
Loss and loss adjustment expense, net	365,162	330,746
Policy acquisition costs, net	75,211	69,041
Other operating expense	77,483us-gaap_OtherCostAndExpenseOperating	87,052us-gaap_OtherCostAndExpenseOperating
Interest expense	7,766us-gaap_InterestExpenseDebt	7,119us-gaap_InterestExpenseDebt
Total expense	525,622us-gaap_BenefitsLossesAndExpenses	493,958us-gaap_BenefitsLossesAndExpenses
Earnings before income taxes	150,828	154,972
Income tax expense	37,911us-gaap_IncomeTaxExpenseBenefit	47,061us-gaap_IncomeTaxExpenseBenefit
Net earnings	$ 112,917us-gaap_NetIncomeLoss	$ 107,911us-gaap_NetIncomeLoss
Earnings per common share
Basic	$ 1.17us-gaap_EarningsPerShareBasic	$ 1.08us-gaap_EarningsPerShareBasic
Diluted	$ 1.17us-gaap_EarningsPerShareDiluted	$ 1.07us-gaap_EarningsPerShareDiluted

The total amount of expense recognized during the period for future policy benefits, claims and claims adjustment costs, and for selling, general and administrative costs.

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