Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available for sale, amortized cost	$ 1,241,339	$ 1,308,333
Available for sale, at cost	$ 119,515	$ 100,157
Ordinary shares, par value	$ 0.0001	$ 0.0001
Ordinary shares, shares authorized	900,000,000	900,000,000
Ordinary Shares A
Ordinary shares, shares issued	13,436,548	16,424,546
Ordinary shares, shares outstanding	13,436,548	13,313,751
Treasury shares, cost	0	3,110,795
Ordinary Shares B
Ordinary shares, shares issued	4,133,366	4,133,366
Ordinary shares, shares outstanding	4,133,366	4,133,366