Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Fixed maturities, at amortized cost	$ 5,584,599	$ 5,556,900
Short-term investments, at amortized cost	2,796,358	1,941,615
Other investments, at amortized cost	380,130	315,963
Investments in investment affiliates, at cost	84,840	69,794
Investments in operating affiliates, at cost	$ 0	$ 392
Shareholders' equity
Preferred Stock, Shares Issued	6,000	0
Preferred Stock, Shares Outstanding	6,000	0
Common shares, par value	$ 0.175	$ 0.175
Common shares, shares issued	161,279,976	160,570,772
Common shares, shares outstanding	79,132,252	82,900,617
Treasury stock, common shares	82,147,724	77,670,155