CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Fixed maturities, available for sale, amortized cost	$ 12,428,133	$ 11,987,146
Equity securities, available for sale, cost	614,174	566,219
Short term investments, amortized cost	$ 100,166	$ 46,212
Common shares, shares issued	175,315	174,134
Common shares, shares outstanding	103,906	109,485
Treasury shares, shares	71,409	64,649