Stock-Based Compensation (Details 2) - $ / shares	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Stock options outstanding (in shares)	110,494	110,494	214,184	216,859
Outstanding options, weighted-average exercise price (in dollars per share)	$ 8.67	$ 8.67	$ 8.60	$ 8.80
Outstanding options, weighted-average remaining contractual life (Year)	1 year 4 months 10 days
Stock options exercisable (in shares)		88,395
Exercisable options, weighted-average exercise price (in dollars per share)		$ 7.13
Range 1 [Member]
Outstanding options, exercise price range, lower limit (in dollars per share)	$ 5.76
Outstanding options, exercise price range, upper limit (in dollars per share)	$ 10.72
Stock options outstanding (in shares)		97,995
Outstanding options, weighted-average exercise price (in dollars per share)		$ 5.76
Outstanding options, weighted-average remaining contractual life (Year)	9 months 10 days
Stock options exercisable (in shares)		80,646
Exercisable options, weighted-average exercise price (in dollars per share)		$ 5.76
Range 2 [Member]
Outstanding options, exercise price range, lower limit (in dollars per share)	$ 10.73
Outstanding options, exercise price range, upper limit (in dollars per share)	$ 11.40
Stock options outstanding (in shares)		5,089
Outstanding options, weighted-average exercise price (in dollars per share)		$ 11.17
Outstanding options, weighted-average remaining contractual life (Year)	3 years 7 months 17 days
Stock options exercisable (in shares)		5,089
Exercisable options, weighted-average exercise price (in dollars per share)		$ 11.17
Range 3 [Member]
Outstanding options, exercise price range, lower limit (in dollars per share)	$ 11.41
Outstanding options, exercise price range, upper limit (in dollars per share)	$ 24.86
Stock options outstanding (in shares)		660
Outstanding options, weighted-average exercise price (in dollars per share)		$ 20.03
Outstanding options, weighted-average remaining contractual life (Year)	4 years 9 months 25 days
Stock options exercisable (in shares)		660
Exercisable options, weighted-average exercise price (in dollars per share)		$ 20.03
Range 4 [Member]
Outstanding options, exercise price range, lower limit (in dollars per share)	$ 24.87
Outstanding options, exercise price range, upper limit (in dollars per share)	$ 49.91
Stock options outstanding (in shares)		6,750
Outstanding options, weighted-average exercise price (in dollars per share)		$ 47.83
Outstanding options, weighted-average remaining contractual life (Year)	7 years 10 months 13 days
Stock options exercisable (in shares)		2,000
Exercisable options, weighted-average exercise price (in dollars per share)		$ 47.62