CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 50,261	$ 28,527	$ 69,862
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of intangibles	6,258	8,599	7,205
Net realized and unrealized (gains) losses on investments	(1,907)	(481)	(6,604)
Foreign exchange gains	(1,638)	(323)	580
Amortization of share-based compensation expense, bond premium and discount and subordinated debt discount, net	10,949	22,236	(3,586)
Changes in assets - (increase) decrease:
Reinsurance balances receivable, net	(98,987)	(168,338)	(29,036)
Funds withheld	917	16,074	(152,713)
Prepaid reinsurance premiums	(3,344)	(6,389)	(240)
Reinsurance recoverable on unpaid losses	(90,567)	(13,632)	1,684
Accrued investment income	(7,719)	836	(2,686)
Deferred commission and other acquisition expenses	(22,073)	(45,037)	(30,648)
Other assets	(13,277)	(14,422)	1,583
Changes in liabilities - increase (decrease):
Reserve for loss and loss adjustment expenses	337,348	176,869	220,932
Unearned premiums	103,796	178,436	68,413
Accrued expenses and other liabilities	49,072	(1,685)	6,833
Net cash provided by operating activities	319,089	181,270	151,579
Cash flows from investing activities:
Purchases of fixed-maturity securities - available-for-sale	(1,193,768)	(636,141)	(1,010,142)
Purchases of fixed-maturity securities – trading and short sale	(102,073)	(663,339)	(1,293,386)
Purchases of other investments	(940)	(1,173)	(424)
Proceeds from sales of fixed-maturity securities - available-for-sale	142,694	304,499	331,593
Proceeds from sales of fixed-maturity securities – trading and short sales	49,883	720,100	1,291,843
Proceeds from maturities and calls of fixed maturity securities	484,091	310,526	507,326
Proceeds from redemption of other investments	340	4,896	108
(Increase) decrease in restricted cash and cash equivalents	(17,432)	(25,139)	55,657
Acquisition of subsidiaries (net of cash acquired)	0	635	(4,893)
Purchase of capital assets	(341)	(1,538)	(2,875)
Net cash (used in) provided by investing activities	(637,546)	13,326	(125,193)
Cash flows from financing activities:
Repurchase agreements, net	0	(76,225)	(19,176)
Senior notes issuance, net of issuance costs	96,594	104,689	0
Repayment of junior subordinated debt	0	(107,500)	0
Preference shares - Series A issuance, net of issuance costs	145,041	0	0
Contribution of noncontrolling interest	0	0	279
Common share issuance	478	422	52
Dividends paid to common shareholders	(29,630)	(20,921)	(18,394)
Dividends paid on preference shares	(3,644)	0	0
Net cash provided by (used in) financing activities	208,839	(99,535)	(37,239)
Effect of exchange rate changes on foreign currency cash	3,079	(3,130)	(392)
Net (decrease) increase in cash and cash equivalents	(106,539)	91,931	(11,245)
Cash and cash equivalents, beginning of period	188,082	96,151	107,396
Cash and cash equivalents, end of period	81,543	188,082	96,151
Supplemental information about non cash investing and financing activities:
Interest paid	36,219	36,850	36,400
Taxes paid	55	429	129
Acquisition of fixed maturities, available-for-sale	0	81,930	17,806
Funds withheld	0	(81,930)	0
Reinsurance balances receivable	0	0	(17,806)
Additional paid-in capital	0	0	18
Common shares issued in exchange of warrants	0	0	(18)
Redemption of other investment	0	0	(4,751)
Purchase of other investment	$ 0	$ 0	$ 4,751