Stock Compensation Plan - Schedule of Stock Option Plans and Changes in Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation Related Costs [Abstract]
Outstanding at beginning of year, Shares	1,760,000	1,560,500	1,301,000
Granted, Shares	576,000	527,000	425,000
Exercised, Shares	(547,900)	(277,500)	(22,500)
Forfeited, shares	(10,000)	0	(37,000)
Expired, Shares	0	(50,000)	(106,000)
Outstanding at end of year, Shares	1,778,100	1,760,000	1,560,500
Options exercisable at end of year	1,202,100	1,233,000	1,135,500
Outstanding at beginning of year, Weighted Average Exercise Price	$ 9.97	$ 9.92	$ 10.34
Weighted Average Exercise Price, Granted	14.96	9.77	9.82
Weighted Average Exercise Price, Exercised	9.92	8.96	7.56
Weighted Average Exercise Price, Forfeited	9.77	0	10.63
Weighted Average Exercise Price, Expired	0	11.97	14.84
Outstanding at end of year, Weighted Average Exercise Price	11.60	9.97	9.92
Weighted-average fair value of options granted during the year	$ 1.81	$ 0.81	$ 0.93