CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Net premiums earned	$ 4,709,850	$ 4,371,309	$ 4,587,178
Net investment income	454,301	349,601	478,572
Other insurance related income	23,295	(8,089)	16,444
Net investment gains:
Allowance for expected credit losses	11	(323)	0
Impairment losses	(22)	(1,486)	0
Other-than-temporary impairment ("OTTI") losses	0	0	(6,984)
Other realized and unrealized investment gains	134,290	130,942	98,217
Total net investment gains	134,279	129,133	91,233
Total revenues	5,321,725	4,841,954	5,173,427
Expenses
Net losses and loss expenses	3,008,783	3,281,252	3,044,798
Acquisition costs	921,834	929,517	1,024,582
General and administrative expenses	663,304	579,790	634,831
Foreign exchange losses (gains)	315	81,069	(12,041)
Interest expense and financing costs	62,302	75,049	68,107
Reorganization expenses	0	7,881	37,384
Amortization of value of business acquired	3,854	5,139	26,722
Amortization of intangible assets	12,424	11,390	11,597
Total expenses	4,672,816	4,971,087	4,835,980
Income before income taxes and interest in income of equity method investments	648,909	(129,133)	337,447
Income tax (expense) benefit	(62,384)	12,321	(23,692)
Interest in income (loss) of equity method investments	32,084	(3,612)	9,718
Net income (loss)	618,609	(120,424)	323,473
Preferred share dividends	30,250	30,250	41,112
Net income (loss) available (attributable) to common shareholders	$ 588,359	$ (150,674)	$ 282,361
Earnings (loss) per common share:
Earnings (loss) per common share (in dollars per share)	$ 6.95	$ (1.79)	$ 3.37
Earnings (loss) per diluted common share (in dollars per share)	$ 6.90	$ (1.79)	$ 3.34
Weighted average common shares outstanding (in shares)	84,707	84,262	83,894
Weighted average diluted common shares outstanding (in shares)	85,291	84,262	84,473