Segments (Textuals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net (favorable) adverse loss development	$ (56,357,000)	$ (73,742,000)	$ (70,011,000)
Internal Claims Department Costs	36,400,000	32,400,000	32,600,000
Professional Liability [Member]
Segment Reporting Information [Line Items]
Total net (favorable) adverse loss development	973,000	(26,346,000)	(25,897,000)
International [Member]
Segment Reporting Information [Line Items]
Total net (favorable) adverse loss development	25,050,000	43,805,000	(10,084,000)
International [Member] | Surety & Credit [Member]
Segment Reporting Information [Line Items]
Total net (favorable) adverse loss development	$ 44,100,000	$ 70,300,000