CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 19,855,000	$ 48,386,000
Adjustments to reconcile net income to net cash used in operating activities:
Net realized investment losses	25,050,000	66,508,000
Net realized and unrealized gains (losses) on other investments	(18,211,000)	27,177,000
Amortization of fixed maturities	12,498,000	19,100,000
Interest in loss of equity method investments	5,766,000	0
Other amortization and depreciation	6,467,000	5,294,000
Share-based compensation expense, net of cash payments	(24,758,000)	(1,357,000)
Non-cash foreign exchange losses	24,149,000	0
Changes in:
Accrued interest receivable	5,596,000	2,616,000
Reinsurance recoverable balances	348,942,000	(6,668,000)
Deferred acquisition costs	(171,493,000)	(175,038,000)
Prepaid reinsurance premiums	(86,534,000)	(37,732,000)
Reserve for loss and loss expenses	(237,773,000)	50,132,000
Unearned premiums	654,475,000	820,947,000
Insurance and reinsurance balances, net	(559,456,000)	(737,185,000)
Other items	(40,834,000)	(96,430,000)
Net cash used in operating activities	(36,261,000)	(14,250,000)
Cash flows from investing activities:
Fixed maturities	(2,670,518,000)	(2,556,709,000)
Equity securities	(98,559,000)	(102,963,000)
Mortgage loans	0	(61,263,000)
Other investments	(63,742,000)	(117,622,000)
Equity method investments	(1,000,000)	0
Short-term investments	(2,320,000)	(13,931,000)
Proceeds from the sale of:
Fixed maturities	2,429,084,000	2,473,167,000
Equity securities	70,575,000	85,254,000
Other investments	131,777,000	47,562,000
Short-term investments	7,087,000	16,331,000
Proceeds from redemption of fixed maturities	521,716,000	246,147,000
Proceeds from redemption of short-term investments	111,931,000	2,282,000
Proceeds from the repayment of mortgage loans	10,233,000	0
Purchase of other assets	(4,427,000)	(44,721,000)
Change in restricted cash and cash equivalents	(84,294,000)	11,627,000
Net cash provided by (used in) investing activities	357,543,000	(14,839,000)
Cash flows from financing activities:
Repurchase of common shares	(143,809,000)	(136,011,000)
Dividends paid - common shares	(38,541,000)	(36,636,000)
Dividends paid - preferred shares	(14,841,000)	(10,003,000)
Repurchase of preferred shares	0	(2,843,000)
Proceeds from issuance of common shares	0	1,783,000
Net cash used in financing activities	(197,191,000)	(183,710,000)
Effect of exchange rate changes on foreign currency cash and cash equivalents	1,678,000	1,986,000
Increase (decrease) in cash and cash equivalents	125,769,000	(210,813,000)
Cash and cash equivalents - beginning of period	1,039,494,000	988,133,000
Cash and cash equivalents - end of period	$ 1,165,263,000	$ 777,320,000