UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Short-term investments, available-for-sale, at fair value, amortized cost	$ 299,733	$ 308,790
Ordinary shares, par value (in dollars per share)	$ 1	$ 1
Ordinary shares, authorized (in shares)	156,000,000	156,000,000
Treasury shares at cost (in shares)	388,571	2,972,892
Voting Common Stock
Ordinary shares issued (in shares)	16,166,652	16,133,334
Ordinary shares outstanding (in shares)	16,166,652	16,133,334
Series A Non-Voting Convertible Ordinary Shares
Ordinary shares issued (in shares)		2,972,892
Series C Non-Voting Convertible Ordinary Shares
Ordinary shares issued (in shares)	2,725,637	2,725,637
Ordinary shares outstanding (in shares)	2,725,637	2,725,637
Series E Non-Voting Convertible Ordinary Shares
Ordinary shares issued (in shares)	404,771	404,771
Ordinary shares outstanding (in shares)	404,771	404,771
Series C Preferred Shares
Preferred shares issued (in shares)	388,571
Preferred shares outstanding (in shares)	388,571
Short-term Investments
Short-term investments, available-for-sale, at fair value, amortized cost	$ 2,406	$ 8,630
Fixed Maturity Investments
Short-term investments, available-for-sale, at fair value, amortized cost	$ 297,327	$ 300,160