Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Cash Provided by (Used in) Operating Activities	$ 506,805	$ 491,929
Cash flows from investing activities:
Proceeds from Sales of Fixed-Maturity Investments Available for sale	770,393	577,034
Proceeds from Sales of Trading Securities	120,875	35,182
Proceeds from Sales of Equity Securities	52,295	92,702
Proceeds from Redemption of Fixed-Maturity Investments Available for sale	287,557	337,857
Proceeds from Redemptions of Trading securities	36,827	53,437
Purchases of Fixed-Maturity Investments Available for sale	(1,352,883)	(1,307,335)
Purchases of Equity Securities	(45,748)	(59,625)
Sales, Redemptions and (Purchases) of Short-term Investments, Net	(12,199)	(216,778)
Sales, Redemptions and (Purchases) of Other assets and other invested assets, net	687	2,111
Purchases of property and equipment, net	(20,707)	(20,323)
Acquisitions, net of cash acquired	0	(662)
Net cash provided by (used in) investing activities	(162,903)	(506,400)
Cash flows from financing activities:
Dividends paid	(1,559)	(1,606)
Issuance of senior notes, net	442,498	0
Repayments and repurchases of senior notes	(610,739)	0
Issuance of common stock	2,126	1,128
Repurchases of common shares	(275,185)	(50,053)
Credit facility commitment fees paid	(710)	(643)
Change in secured borrowings, net (with terms less than 3 months)	9,568	41,414
Proceeds from secured borrowings (with terms greater than 3 months)	73,011	45,458
Payments of secured borrowings (with terms greater than 3 months)	(37,550)	(3,000)
Repayments of other borrowings	(114)	(133)
Net cash provided by (used in) financing activities	(398,654)	32,565
Effect of exchange rate changes on cash and restricted cash	(4)	0
Increase (decrease) in cash and restricted cash	(54,756)	18,094
Cash and restricted cash, beginning of period	107,002	96,244
Cash and restricted cash, end of period	$ 52,246	$ 114,338