Schedule VI. Supplemental Information Concerning Property and Casualty Insurance Operations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Net Realized Investment Gains (Losses)	$ 5,453		$ 6,440		$ 8,489
Amortization of the value of business acquired asset	1,673		25,763		0
Consolidated Property and Casualty Insurance Entity [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred Policy Acquisition Costs	64,947		60,668		44,681
Reserves for Unpaid Claims and Claims Adjustment Expenses	971,911		945,051		603,090
Unearned Premiums	311,561		288,868		200,151
Earned Premiums	629,411		533,771		420,373
Net Realized Investment Gains (Losses)	1,676		3,081		3,593
Net Investment Income	41,879		35,513		34,787
Current Year Claims and Claims Adjustment Expenses	512,564		468,926		335,315
Prior Year Claims and Claims Adjustment Expenses	(73,427)		(61,095)		(45,878)
Amortization of Deferred Policy Acquisition Costs	134,444	[1]	143,952	[1]	100,310	[1]
Paid Claims and Claims Adjustment Expenses	395,788		399,828		297,638
Premiums Written	655,331		551,923		414,908
Mercer Insurance Group [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Amortization of the value of business acquired asset	$ 1,673		$ 25,763

[1] 2012 and 2011 include amortization of the value of business acquired asset that was recorded as a result of our acquisition of Mercer Insurance Group, Inc. totaling $1,673 and $25,763, respectively.