CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums earned	$ 4,791,495	$ 4,148,760	$ 3,705,625
Net investment income	438,507	400,805	353,335
Other insurance related income (losses)	10,622	(1,240)	7,222
Bargain purchase gain	0	15,044	0
Net investment gains (losses):
Other-than-temporary impairment (OTTI) losses	(9,733)	(14,493)	(26,210)
Other realized and unrealized investment gains (losses)	(140,485)	42,719	(34,315)
Total net investment gains (losses)	(150,218)	28,226	(60,525)
Total revenues	5,090,406	4,591,595	4,005,657
Expenses
Net losses and loss expenses	3,190,287	3,287,772	2,204,197
Acquisition costs	968,835	823,591	746,876
General and administrative expenses	627,389	579,428	602,717
Foreign exchange losses (gains)	(29,165)	134,737	(121,295)
Interest expense and financing costs	67,432	54,811	51,360
Transaction and reorganization expenses	66,940	26,718	0
Amortization of value of business acquired	172,332	50,104	0
Amortization of intangible assets	13,814	2,543	0
Total expenses	5,077,864	4,959,704	3,483,855
Income (loss) before income taxes and interest in income (loss) of equity method investments	12,542	(368,109)	521,802
Income tax (expense) benefit	29,486	7,542	(6,340)
Interest in income (loss) of equity method investments	993	(8,402)	(2,094)
Net income (loss)	43,021	(368,969)	513,368
Preferred share dividends	42,625	46,810	46,597
Loss on repurchase of preferred shares	0	0	1,309
Net income (loss) available (attributable) to common shareholders	$ 396	$ (415,779)	$ 465,462
Earnings (loss) per common share:
Earnings (loss) per common share (in dollars per share)	$ 0.00	$ (4.94)	$ 5.13
Earnings (loss) per diluted common share (in dollars per share)	$ 0.00	$ (4.94)	$ 5.08
Weighted average common shares outstanding (in shares)	83,501	84,108	90,772
Weighted average diluted common shares outstanding (in shares)	84,007	84,108	91,547