Fair Value of Financial Instruments (Level 3 Securities) (Details) - Recurring $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 15,098
Net unrealized gains (losses)	(60)
Purchases	145
Disposals	(347)
Ending Balance	14,836
States, municipalities and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	168
Net unrealized gains (losses)	0
Purchases	0
Disposals	0
Ending Balance	168
Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	9,894
Net unrealized gains (losses)	(67)
Purchases	0
Disposals	(333)
Ending Balance	9,494
Asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	449
Net unrealized gains (losses)	7
Purchases	0
Disposals	0
Ending Balance	456
Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,587
Net unrealized gains (losses)	0
Purchases	145
Disposals	(14)
Ending Balance	$ 4,718