Schedule II - Condensed Financial Information of Registrant - Condensed Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities
Net income	$ 58,977	$ 30,312	$ 20,109
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized (gains) losses on investments	14,740	11,943	(2,350)
Net change in unrealized (gains) losses on investments	(7,850)	(9,443)	18,410
Deferred income taxes	7,363	3,813	(9,543)
Excess tax benefits from stock-based compensation	(359)	1,760	(195)
Other	10	6	(17)
Net changes in assets and liabilities relating to operating activities:
Restricted cash and cash equivalents	30,409	45,304	(64,372)
Purchases of equity securities, trading	(26,009)	(343,962)	(801,704)
Proceeds from sale of equity securities, trading	102,661	360,000	921,625
Income taxes recoverable	(5,558)	(2,594)
Income taxes payable	2,226	(13,801)	4,653
Net cash provided by (used in) operating activities	156,959	142,506	112,584
Cash flows from investing activities:
Purchases of equity securities, available for sale	(77,859)
Purchase of fixed maturities, available for sale	(305,330)
Net cash used in investing activities	(352,683)	(2,698)	(2,331)
Cash flows from financing activities:
Proceeds from borrowings	20,000
Preferred stock dividend	(29)	(287)	(20)
Common stock dividend	(17,725)	(18,669)	(12,750)
Issuance of common stock		207	5
Purchase of treasury stock	(32,366)
Payments related to tax withholding for share-based compensation	(3,161)	(121)	(172)
Excess tax benefits (shortfall) from stock-based compensation	359	(1,760)	195
Net cash provided by (used in) financing activities	(34,393)	(22,101)	(14,213)
Net increase (decrease) in cash and cash equivalents	(230,117)	117,707	96,040
Cash and cash equivalents at beginning of period	347,392	229,685	133,645
Cash and cash equivalents at end of period	117,275	347,392	229,685
Parent Company [Member]
Cash flows from operating activities
Net income	58,977	30,312	20,109
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in net income of subsidiaries	(78,600)	(38,916)	(22,568)
Amortization of stock-based compensation	6,417	3,830	2,848
Net realized (gains) losses on investments	2,947	1,880	1,186
Net change in unrealized (gains) losses on investments	(1,625)	(1,162)	3,009
Deferred income taxes	7,363	3,813	(9,543)
Excess tax benefits from stock-based compensation	(359)	1,760	(195)
Other			5
Net changes in assets and liabilities relating to operating activities:
Restricted cash and cash equivalents		30,220	(18,880)
Purchases of equity securities, trading	(3,972)	(58,836)	(77,691)
Proceeds from sale of equity securities, trading	16,712	60,379	66,526
Income taxes recoverable	(5,558)	(2,594)
Income taxes payable	2,226	(13,801)	4,653
Other operating assets and liabilities	1,347	2,911	1,405
Net cash provided by (used in) operating activities	5,875	19,796	(29,136)
Cash flows from investing activities:
Capital contributions to subsidiaries	(1,600)	(28,555)	(49,001)
Distribution of income from subsidiaries	26,898	40,222	89,322
Purchases of equity securities, available for sale	(10,357)
Purchase of fixed maturities, available for sale	(750)
Net cash used in investing activities	14,191	11,667	40,321
Cash flows from financing activities:
Proceeds from borrowings	20,000
Preferred stock dividend	(29)	(287)	(20)
Common stock dividend	(17,725)	(18,669)	(12,750)
Issuance of common stock		207	5
Purchase of treasury stock	(32,365)
Payments related to tax withholding for share-based compensation	(3,161)	(121)	(172)
Excess tax benefits (shortfall) from stock-based compensation	359	(1,760)	195
Net cash provided by (used in) financing activities	(32,921)	(20,630)	(12,742)
Net increase (decrease) in cash and cash equivalents	(12,855)	10,833	(1,557)
Cash and cash equivalents at beginning of period	17,733	6,900	8,457
Cash and cash equivalents at end of period	$ 4,878	$ 17,733	$ 6,900

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.