CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 115,542	$ 177,846
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment losses	29,443	45,500
Net realized and unrealized gains (losses) on other investments	(40,226)	14,406
Amortization of fixed maturities	20,740	35,186
Interest in loss of equity method investments	7,741	0
Other amortization and depreciation	12,638	11,255
Share-based compensation expense, net of cash payments	(10,846)	16,617
Non-cash foreign exchange losses	24,149	0
Bargain purchase gain	(15,044)	0
Changes in:
Accrued interest receivable	4,208	2,262
Reinsurance recoverable balances	242,437	(103,215)
Deferred acquisition costs	(151,633)	(152,777)
Prepaid reinsurance premiums	(180,107)	(100,699)
Reserve for loss and loss expenses	8,015	128,661
Unearned premiums	724,407	937,950
Insurance and reinsurance balances, net	(540,557)	(859,502)
Other items	(102,014)	(90,954)
Net cash provided by operating activities	148,893	62,536
Cash flows from investing activities:
Fixed maturities	(4,766,037)	(4,687,409)
Equity securities	(101,289)	(215,324)
Mortgage loans	(10,207)	(120,923)
Other investments	(107,020)	(173,127)
Equity method investments	(1,000)	(103,548)
Short-term investments	(9,029)	(27,800)
Proceeds from the sale of:
Fixed maturities	3,955,065	4,559,910
Equity securities	127,182	210,810
Other investments	177,238	110,077
Short-term investments	13,539	18,291
Proceeds from redemption of fixed maturities	1,043,002	558,715
Proceeds from redemption of short-term investments	116,111	2,539
Proceeds from the repayment of mortgage loans	10,467	0
Purchase of other assets	(12,205)	(13,313)
Change in restricted cash and cash equivalents	(84,738)	(13,909)
Purchase of subsidiary, net of cash acquired	(78,872)	0
Net cash provided by investing activities	272,207	104,989
Cash flows from financing activities:
Repurchase of common shares	(286,962)	(263,050)
Dividends paid - common shares	(71,189)	(69,347)
Dividends paid - preferred shares	(31,532)	(19,971)
Repurchase of preferred shares	(351,074)	(2,843)
Proceeds from issuance of common shares	0	8
Net cash used in financing activities	(740,757)	(355,203)
Effect of exchange rate changes on foreign currency cash and cash equivalents	8,682	(7,510)
Decrease in cash and cash equivalents	(310,975)	(195,188)
Cash and cash equivalents - beginning of period	1,039,494	988,133
Cash and cash equivalents - end of period	$ 728,519	$ 792,945