Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net income	$ 100,209	$ 72,031
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on the sale of investments, net	(1,054)	(1,217)
Depreciation and amortization	2,040	1,581
Stock-based compensation expense	7,949	6,596
Amortization of premium on investment securities	5,218	4,835
Deferred income tax provision	28,264	28,961
Excess tax benefits from stock-based compensation	(1,023)	(2,332)
Change in:
Accrued investment income	(712)	(1,195)
Accounts receivable	(2,478)	(1,162)
Deferred policy acquisition costs	(710)	(949)
Prepaid federal income tax	(30,360)	(35,500)
Other assets	(375)	(3,486)
Reserve for losses and LAE	4,714	3,504
Unearned premium reserve	13,865	21,257
Accrued liabilities	(3,480)	(3,078)
Net cash provided by operating activities	122,067	89,846
Investing Activities
Net change in short-term investments	(43,239)	115,322
Purchase of investments available for sale	(268,024)	(417,541)
Proceeds from maturity of investments available for sale	9,043	7,525
Proceeds from sales of investments available for sale	178,719	212,208
Purchase of property and equipment, net	(2,049)	(2,932)
Net cash used in investing activities	(125,550)	(85,418)
Financing Activities
Payment of issuance costs for revolving line of credit	(2,098)	0
Treasury stock acquired	(3,876)	(5,078)
Excess tax benefits from stock-based compensation	1,023	2,332
Payment of offering costs	0	(537)
Other financing activities	0	34
Net cash used in financing activities	(4,951)	(3,249)
Net (decrease) increase in cash	(8,434)	1,179
Cash at beginning of year	24,606	24,411
Cash at end of period	16,172	25,590
Supplemental Disclosure of Cash Flow Information
Income tax payments	$ (10,800)	$ (5,000)