Stockholders' Equity (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassifications included in net income:
Net of tax	$ (475)	$ 1,115	$ 908	$ 1,948
Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Pre-tax	(871)	952	(23)	1,582
Tax (expense) benefit	396	163	931	366
Net of tax	(475)	1,115	908	1,948
Realized gain on sale of available for sale investment securities | Investment and other income | Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Pre-tax	459	1,404	2,804	2,586
Tax (expense) benefit	(170)	(520)	(1,040)	(957)
Net of tax	289	884	1,764	1,629
Change in valuation allowance for unrealized gains (losses) on investment securities
Reclassifications included in net income:
Net of tax	169	516	1,020	951
Change in valuation allowance for unrealized gains (losses) on investment securities | Provision for income taxes | Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Tax (expense) benefit	169	516	1,020	951
Net of tax	169	516	1,020	951
Pension and postretirement benefits
Reclassifications included in net income:
Net of tax	(933)	(285)	(1,876)	(632)
Pension and postretirement benefits | Underwriting and distribution expense and Compensation and related costs | Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Pre-tax	(1,330)	(452)	(2,827)	(1,004)
Tax (expense) benefit	397	167	951	372
Net of tax	$ (933)	$ (285)	$ (1,876)	$ (632)