Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net earnings	$ 149,360	$ 154,653
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Depreciation and amortization	35,663	34,905
Net realized capital (gains) losses	(59,651)	(35,893)
Other than temporary impairment losses	3,217	20,759
(Increase) decrease in reinsurance recoverables, net of reinsurance payable	34,196	65,627
(Increase) decrease in premium balances receivable	(62,971)	(3,708)
(Increase) decrease in ceded unearned premiums	(17,874)	2
(Increase) decrease in deferred acquisition costs	(6,488)	(30,197)
(Increase) decrease in funds held under reinsurance agreements	(23,885)	(170,912)
Increase (decrease) in unearned premiums	39,448	93,998
Increase (decrease) in loss and loss adjustment expenses	(97,254)	(40,512)
Change in unrealized foreign exchange losses (gains)	(19,971)	45,552
Other, net	(16,322)	(94,694)
Net adjustments	(191,892)	(115,073)
Net cash provided by (used in) operating activities	(42,532)	39,580
Cash flows from investing activities
Purchases of debt securities	(1,811,566)	(1,844,101)
Purchases of equity securities	(304,343)	(551,815)
Sales of debt securities	1,349,608	1,800,873
Maturities and redemptions of debt securities	443,960	237,162
Sales of equity securities	1,363,269	665,994
Net (purchases) sales of short-term investments	(949,847)	(142,622)
Net (purchases) sales and maturities of commercial mortgage loans	(24,803)	(101,959)
Purchases of property and equipment	(4,480)	(2,088)
Purchases of subsidiaries, net of cash acquired		(1,020)
Other, net	29,388	(20,329)
Net cash provided by (used in) investing activities	91,186	40,095
Cash flows from financing activities
Treasury stock acquisitions		(53,288)
Increase (decrease) in other debt	(5,509)	4,508
Other, net	(13,057)	1,226
Net cash provided by (used in) financing activities	(18,566)	(47,554)
Effect of exchange rate changes on cash	266	2,355
Net increase (decrease) in cash	30,354	34,476
Cash at beginning of period	594,091	475,267
Cash at end of period	624,445	509,743
Cash paid during period for:
Interest paid	16,359	16,115
Income taxes paid (refund received)	$ 5,949	$ 11,737