Significant Accounting Policies - Stock Transactions - Stock Option Plans (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Shares
Options Outstanding, beginning shares			522,338
Options granted, shares	0	0	97,900	44,000
Options exercised, shares	(4,620)	(578)	(24,998)	(578)
Options forfeited, shares			(1,833)
Options expired, shares			(4,275)
Options Outstanding, ending shares	589,132		589,132		522,338
Shares Exercisable	423,582		423,582
Weighted average exercise price
Weighted average exercise price, Options Outstanding, beginning (in dollars per share)			$ 6.45
Weighted average exercise price, Options granted (in dollars per share)	$ 0.00	$ 0.00	10.06	$ 8.30
Weighted average exercise price, Options exercised (in dollars per share)			5.38
Weighted average exercise price, Options forfeited (in dollars per share)			7.00
Weighted average exercise price, Options expired (in dollars per share)			7.64
Weighted average exercise price, Options Outstanding, ending (in dollars per share)	7.08		7.08		$ 6.45
Weighted average exercise price, Options Exercisable (in dollars per share)	$ 6.18		$ 6.18
Weighted average remaining contractual life , Options Outstanding			5 years 2 months 12 days		5 years 1 month 6 days
Weighted average remaining contractual life, Options exercisable			3 years 8 months 12 days
Aggregate intrinsic value: Options Outstanding	$ 3,378,979		$ 3,378,979		$ 2,561,095
Aggregate intrinsic value, Options exercisable	$ 2,813,837		$ 2,813,837