Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2012 Carrying Amount [Member]	Dec. 31, 2011 Carrying Amount [Member]	Jun. 30, 2012 Fair Value [Member]	Dec. 31, 2011 Fair Value [Member]	May 31, 2012 ACT II [Member]	Jun. 30, 2012 ACT II [Member] Carrying Amount [Member]	Dec. 31, 2011 ACT II [Member] Carrying Amount [Member]	Jun. 30, 2012 ACT II [Member] Fair Value [Member]	Dec. 31, 2011 ACT II [Member] Fair Value [Member]
Summary of carrying or reported values and corresponding fair values for financial instruments
Fixed maturity securities-held-to-maturity	$ 620,682	$ 646,048			$ 620,682	$ 646,048	$ 662,917	$ 685,242
Fixed maturity securities-available-for-sale	128,565	100,742			128,565	100,742	128,565	100,742
Equity securities	8,293	12,240			8,293	12,240	8,293	12,240
Cash and cash equivalents	76,848	45,536	62,044	60,966	76,848	45,536	76,848	45,536
Short-term Investments	43,751	46,944			43,751	46,944	43,751	46,944
Subordinated debt securities:	$ 12,890	$ 25,780							$ 12,890	$ 12,890	$ 25,780	$ 12,890	$ 25,780