Stock-Based Compensation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summary the stock option transactions
Forfeited/canceled/expired	(59,000)
Stock Option Plan [Member]
Summary the stock option transactions
Number of Options Outstanding	213,170	233,787	260,660
Granted	0	0	0
Exercised	(125,354)	(7,294)	(8,910)
Forfeited/canceled/expired	(58,781)	(13,323)	(17,963)
Number of Options Outstanding	29,035	213,170	233,787	260,660
Number of Options Vested and Exercisable	29,035
Weighted Average Exercise Price, Outstanding	$ 31.79	$ 33.38	$ 34.69
Weighted Average Exercise Price, Granted	0	0	0
Weighted Average Exercise Price, Exercised	27.09	34.8	29.41
Weighted Average Exercise Price, Forfeited/canceled/expired	43.47	57.93	54.35
Weighted Average Exercise Price, Outstanding	28.47	$ 31.79	$ 33.38	$ 34.69
Weighted Average Exercise Price Vested and Exercisable	$ 28.47
Weighted Average Remaining Contractual Term (Years)	1 year 4 months 24 days	1 year 2 months 12 days	2 years 1 month 6 days	3 years
Weighted Average Remaining Contractual Term (Years) Vested and Exercisable	1 year 4 months 24 days
Aggregate Intrinsic Value Outstanding	$ 2,519,147	$ 4,058,035	$ 1,253,039
Aggregate Intrinsic Value Outstanding	289,769	$ 2,519,147	$ 4,058,035	$ 1,253,039
Aggregate Intrinsic Value Vested and Exercisable	$ 289,769