Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Condensed Consolidated Balance Sheets
Available-for-sale, amortized cost	$ 1,596,227	$ 1,518,156
Equity securities available-for-sale, cost	187,573	202,437
Premiums and reinsurance balances receivable, allowances for uncollectible amounts	15,981	14,898
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	10,699	11,885
Property and equipment, accumulated depreciation	$ 41,999	$ 38,447
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	66,874,911	66,474,342
Common stock, shares outstanding (in shares)	43,944,697	43,544,128
Treasury stock, shares (in shares)	22,930,214	22,930,214