SCHEDULE II-CONDENSED FINANCIAL INFORMATION OF REGISTRANT (PARENT COMPANY) (Details 2) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
CONDENSED BALANCE SHEETS (Parenthetical)
Available-for-sale, amortized cost	$ 1,431,049	$ 1,294,350
Property and equipment, accumulated depreciation	41,491	45,603
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	65,912,638	65,455,462
Common stock, shares outstanding (in shares)	42,982,424	42,525,248
Treasury stock, shares (in shares)	22,930,214	22,930,214
PARENT COMPANY
CONDENSED BALANCE SHEETS (Parenthetical)
Available-for-sale, amortized cost	18,839	19,967
Property and equipment, accumulated depreciation	$ 312	$ 240
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	65,912,638	65,455,462
Common stock, shares outstanding (in shares)	42,982,424	42,525,248
Treasury stock, shares (in shares)	22,930,214	22,930,214