Condensed Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Assets [Abstract]
Fixed maturities, amortized cost	$ 13,562,765	$ 13,376,455
Short-term investments, amortized cost	28,820	13,543
Equities, cost	1,027,732	1,009,286
Funds held - directly managed, cost	756,498	778,569
Shareholders' Equity [Abstract]
Common shares, par value	$ 1	$ 1
Common shares, shares issued	86,879,432	86,657,045
Common shares held in treasury, shares	36,019,611	34,213,611
Preferred shares, par value	$ 1	$ 1
Number of preferred shares issued	34,150,000	34,150,000
Preferred shares, shares outstanding	34,150,000	34,150,000
Aggregate liquidation value	$ 853,750	$ 853,750