Stock-Based Compensation (Details) - Stock Option Plan [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary the stock option transactions
Number of Options, Outstanding	29,035	29,035	213,170
Number of Options, Granted	0	0	0
Number of Options, Exercised	(29,035)	0	(125,354)
Number of Options, Forfeited/canceled/expired	0	0	(58,781)
Number of Options, Outstanding	0	29,035	29,035	213,170
Number of Options, Vested and Exercisable	0
Weighted Average Exercise Price, Outstanding	$ 28.47	$ 28.47	$ 31.79
Weighted Average Exercise Price, Granted	0	0	0
Weighted Average Exercise Price, Exercised	28.47	0	27.09
Weighted Average Exercise Price, Forfeited/canceled/expired	0	0	43.47
Weighted Average Exercise Price, Outstanding	0	$ 28.47	$ 28.47	$ 31.79
Weighted Average Exercise Price, Vested and Exercisable	$ 0
Weighted Average Remaining Contractual Term (Years), Outstanding	0 years	4 months 24 days	1 year 4 months 24 days	1 year 2 months 12 days
Weighted Average Remaining Contractual Term (Years) Vested and Exercisable	0 years
Aggregate Intrinsic Value, Outstanding	$ 0	$ 633,834	$ 289,769	$ 2,519,147
Aggregate Intrinsic Value, Vested and Exercisable	$ 0