Stockholders' Equity (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Pre-tax	$ (4,804)	$ 3,139
Tax (expense) benefit	2,042	739
Net of tax	(2,762)	3,878
Realized loss on sale of sponsored investment securities | Investment and other income (loss) | Reclassifications from accumulated other comprehensive income (loss)
Reclassifications included in net income:
Pre-tax	850	5,146
Tax (expense) benefit	(312)	(1,905)
Net of tax	538	3,241
Change in valuation allowance for unrealized gains (losses) on investment securities
Reclassifications included in net income:
Net of tax	306	1,900
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	306	1,900
Net of tax	306	1,900
Pension and postretirement benefits
Reclassifications included in net income:
Net of tax	(3,606)	(1,263)
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	(5,654)	(2,007)
Tax (expense) benefit	2,048	744
Net of tax	$ (3,606)	$ (1,263)