Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 17,620	$ 20,387
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation	2,085	389
Net amortization of discount and premiums on investments in fixed-maturity securities	206	76
Depreciation and amortization	1,203	619
Deferred income tax benefits	(832)	(1,178)
Net realized investment gains	(4)	(20)
Gain on sale of other investment	(1)
Foreign currency remeasurement (gain) loss	(15)	10
Changes in operating assets and liabilities:
Premiums receivable	(3,359)	(6,483)
Advance premiums	13,063	11,876
Prepaid reinsurance premiums	12,849	(6,923)
Accrued interest and dividends receivable	(205)	103
Other assets	(3,036)	(432)
Assumed reinsurance balances payable	(3,666)	(386)
Deferred policy acquisition costs	(113)	(1,790)
Losses and loss adjustment expenses	(89)	583
Unearned premiums	(14,948)	(13,298)
Income taxes payable	8,049	4,989
Accrued expenses and other liabilities	6,261	6,755
Net cash provided by operating activities	35,068	15,277
Cash flows from investing activities:
Purchase of property and equipment, net	(92)	(2,364)
Purchase of other investments	(320)	(52)
Purchase of fixed-maturity securities	(19,306)	(1,629)
Purchase of equity securities	(7,709)	(1,024)
Proceeds from sales of fixed-maturity securities	1,691	1,037
Proceeds from calls, repayments and maturities of fixed-maturity securities	633	1,237
Proceeds from sales of equity securities	2,764	361
Proceeds from sales of other investments	1
Net cash used in investing activities	(22,338)	(2,434)
Cash flows from financing activities:
Proceeds from the issuance of long-term debt		40,250
Proceeds from the exercise of common stock options	125
Cash dividends paid	(3,206)	(2,493)
Cash dividends received under share repurchase forward contract	171
Repurchases of common stock	(353)
Repurchases of common stock under share repurchase plan	(6,987)
Debt issuance costs	(234)	(1,502)
Tax benefits on stock-based compensation	915	22
Net cash (used in) provided by financing activities	(9,569)	36,277
Effect of exchange rate changes on cash	17	(7)
Net increase in cash and cash equivalents	3,178	49,113
Cash and cash equivalents at beginning of period	293,398	230,214
Cash and cash equivalents at end of period	296,576	279,327
Supplemental disclosure of cash flow information:
Cash paid for income taxes	2,500	8,950
Cash paid for interest	1,847
Non-cash investing and financing activities:
Unrealized gain on investments in available-for-sale securities, net of tax	1,424	165
Series A Preferred Stock [Member]
Non-cash investing and financing activities:
Conversion of Series A Preferred Stock to common stock	$ 910	$ 278