Stockholders' Equity (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassifications included in net income:
Net of tax	$ 835	$ 1,589
Reclassifications from accumulated other comprehensive income
Reclassifications included in net income:
Pre-tax	630	1,022
Tax (expense) benefit	205	567
Net of tax	835	1,589
Realized gain on sale of available for sale investment securities
Reclassifications included in net income:
Net of tax	748	1,535
Realized gain on sale of available for sale investment securities | Investment and other income | Reclassifications from accumulated other comprehensive income
Reclassifications included in net income:
Pre-tax	1,182	2,426
Tax (expense) benefit	(434)	(891)
Net of tax	748	1,535
Valuation allowance
Reclassifications included in net income:
Net of tax	434	900
Valuation allowance | Provision for income taxes | Reclassifications from accumulated other comprehensive income
Reclassifications included in net income:
Tax (expense) benefit	434	900
Net of tax	434	900
Amortization of pension and postretirement benefits
Reclassifications included in net income:
Net of tax	(347)	(846)
Amortization of pension and postretirement benefits | Underwriting and distribution expense and Compensation and related costs | Reclassifications from accumulated other comprehensive income
Reclassifications included in net income:
Pre-tax	(552)	(1,404)
Tax (expense) benefit	205	558
Net of tax	$ (347)	$ (846)