Consolidated Statements of Cash Flow - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities
Net income	$ 120,472	$ 100,477
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	43,868	31,059
Sale of renewal rights	0	(8,000)
Stock-based compensation expense	7,626	7,421
Undistributed losses (gains) of equity method investments	781	(131)
Net realized gains	(15,771)	(26,988)
Changes in assets and liabilities:
Increase in reserve for loss and loss expenses, net of reinsurance recoverables	60,065	86,887
Increase in unearned premiums, net of prepaid reinsurance	121,424	68,935
Decrease in net federal income taxes	27,980	33,596
Increase in premiums receivable	(95,188)	(66,816)
Increase in deferred policy acquisition costs	(28,058)	(16,700)
Decrease (increase) in interest and dividends due or accrued	979	(82)
Decrease in accrued salaries and benefits	(338)	(13,958)
Increase (decrease) in accrued insurance expenses	7,154	(12,545)
Increase (decrease) in other assets and other liabilities	8,039	(25,036)
Net adjustments	138,561	57,642
Net cash provided by operating activities	259,033	158,119
Investing Activities
Purchase of fixed income securities, available-for-sale	(731,154)	(560,493)
Purchase of equity securities, available-for-sale	(192,717)	(185,529)
Purchase of other investments	(6,589)	(8,498)
Purchase of short-term investments	(1,084,794)	(1,082,192)
Sale of fixed income securities, available-for-sale	22,323	35,499
Sale of short-term investments	1,090,911	1,074,850
Redemption and maturities of fixed income securities, held-to-maturity	79,972	56,375
Redemption and maturities of fixed income securities, available-for-sale	403,510	336,939
Sale of equity securities, available-for-sale	148,228	186,001
Distributions from other investments	22,038	13,514
Purchase of property and equipment	(11,869)	(9,178)
Sale of renewal rights	0	8,000
Net cash used in investing activities	(260,141)	(134,712)
Financing Activities
Dividends to stockholders	(22,848)	(20,899)
Acquisition of treasury stock	(3,887)	(2,920)
Net proceeds from stock purchase and compensation plans	6,016	3,554
Proceeds from borrowings	15,000	0
Excess tax benefits from share-based payment arrangements	1,498	1,024
Repayments of capital lease obligations	(3,517)	(1,858)
Net cash used in financing activities	(7,738)	(21,099)
Net (decrease) increase in cash	(8,846)	2,308
Cash, beginning of year	23,959	193
Cash, end of period	$ 15,113	$ 2,501