Unpaid Loss and Loss Adjustment Expenses Change in unpaid loss and loss adjustment expenses property and casualty (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Gross			$ 103,116
Property and casualty	97,923		103,116
Property, Liability and Casualty Insurance Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Gross				120,258
Supplemental Information for Property, Casualty Insurance Underwriters, Reserves for Unpaid Claims and Claims Adjustment Expense	8,019	969	5,478	298
Liability for Claims and Claims Adjustment Expense	89,904	105,088	97,638	119,960
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Current Year	20,950	21,533
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	(789)	242
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	(8,210)	(7,101)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	(19,685)	(29,546)
Property and casualty	$ 97,923	$ 106,057