Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net (losses) earnings	$ (57,928)	$ 390,760
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Depreciation and amortization	106,197	115,020
Net realized capital (gains) losses	(101,840)	(117,126)
Other than temporary impairment losses	13,095	38,216
(Increase) decrease in reinsurance recoverables, net of reinsurance payable	(413,548)	73,781
(Increase) decrease in premium balances receivable	(134,088)	(44,341)
(Increase) decrease in ceded unearned premiums	(7,368)	(17,588)
(Increase) decrease in deferred acquisition costs	(28,000)	(39,962)
(Increase) decrease in funds held under reinsurance agreements	(94,222)	(299,372)
Increase (decrease) in unearned premiums	120,456	164,078
Increase (decrease) in loss and loss adjustment expenses	1,369,176	258,861
Change in unrealized foreign exchange losses (gains)	(134,404)	78,615
Other, net	(211,479)	(27,283)
Net adjustments	483,975	182,899
Net cash provided by (used in) operating activities	426,047	573,659
Cash flows from investing activities
Purchases of debt securities	(4,181,182)	(4,665,980)
Purchases of equity securities	(3,218,941)	(1,163,687)
Sales of debt securities	2,836,272	3,953,367
Maturities and redemptions of debt securities	1,397,408	996,548
Sales of equity securities	2,970,760	1,197,612
Net (purchases) sales of short-term investments	174,501	(417,186)
Net (purchases) sales and maturities of commercial mortgage loans	(54,822)	(336,944)
(Purchases) sales of property and equipment	10,268	(18,982)
Purchases of affiliates and subsidiaries, net of cash acquired	(244,311)	(145,253)
Other, net	28,302	128,731
Net cash provided by (used in) investing activities	(281,745)	(471,774)
Cash flows from financing activities
Treasury stock acquisitions	(8,549)	(55,678)
Increase (decrease) in other debt	(27,202)	43,135
Other, net	(17,070)	(4,274)
Net cash provided by (used in) financing activities	(52,821)	(16,817)
Effect of exchange rate changes on cash	16,269	8,572
Net increase (decrease) in cash	107,750	93,640
Cash at beginning of period	594,091	475,267
Cash at end of period	701,841	568,907
Cash paid during period for:
Interest paid	58,133	56,423
Income taxes paid (refund received)	$ 29,320	$ 51,969