Fair Value of Financial Instruments (Level 3 Securities) (Details) - Continuing and Discontinuing Operations - Recurring - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 10,350	$ 15,098
Net unrealized gains (losses)	141	309
Purchases	100	245
Disposals	(433)	(5,494)
Ending Balance	10,158	10,158
States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	77	168
Net unrealized gains (losses)	0	(6)
Purchases	0	0
Disposals	0	(85)
Ending Balance	77	77
Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	9,056	9,894
Net unrealized gains (losses)	(7)	(6)
Purchases	100	100
Disposals	(433)	(1,272)
Ending Balance	8,716	8,716
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	622	449
Net unrealized gains (losses)	9	182
Purchases	0	0
Disposals	0	0
Ending Balance	631	631
Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	595	4,587
Net unrealized gains (losses)	139	139
Purchases	0	145
Disposals	0	(4,137)
Ending Balance	$ 734	$ 734