Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net Cash Provided by (Used in) Operating Activities	$ 118,447	$ 83,932
Cash flows from investing activities:
Proceeds from Sale and Maturity of Fixed-Maturity Investments Available-for-sale	224,597	253,121
Proceeds from Sale of Securities, Operating Activities	55,795	0
Proceeds from Sale of Trading Securities Held-for-investment	11,964	46,688
Proceeds from Redemption of Fixed-Maturity Investments Available-for-sale	94,356	123,683
Proceeds from Redemption of Trading Securities Held-for-investment	17,890	19,543
Purchases of Fixed-Maturity Investments Available-for-sale	(482,260)	(444,873)
Purchases of Equity Securities	(19,994)	0
Sales, Redemptions and (Purchases) of Short-term Investments, Net	(17,217)	57,923
Sales, Redemptions and (Purchases) of Other assets and other invested assets, net	92	222
Purchases of property and equipment, net	(4,702)	(7,687)
Acquisitions, net of cash acquired	(261)	(86)
Net cash provided by (used in) investing activities	(119,740)	48,534
Cash flows from financing activities:
Dividends paid	(540)	(538)
Purchases and redemptions of senior notes	0	(110,160)
Issuance of common stock	663	2,865
Purchase of common shares	(10,003)	0
Credit facility commitment fees paid	(185)	0
Change in secured borrowings (Note 12)	38,719	0
Proceeds from secured borrowings (with terms greater than 3 months)	6,550	0
Repayment of other borrowings	(50)	(81)
Net cash provided by (used in) financing activities	35,154	(107,914)
Effect of exchange rate changes on cash and restricted cash	(1)	24
Increase (decrease) in cash and restricted cash	33,860	24,576
Cash and restricted cash, beginning of period	96,244	61,814
Cash and restricted cash, end of period	$ 130,104	$ 86,390