Employee Benefit Plans - Transactions Under the Company's Stock Option Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares
Options Outstanding, beginning shares (in shares)	584,178	504,573	552,759
Options granted (in shares)	96,000	203,000	47,100
Options exercised (in shares)	(60,534)	(115,962)	(94,679)
Options forfeited (in shares)	(5,333)	(7,433)	0
Options expired (in shares)	0	0	(607)
Options Outstanding, ending shares (in shares)	614,311	584,178	504,573	552,759
Options Exercisable: Shares Exercisable (in shares)	372,794
Weighted average exercise price
Weighted Average exercise Price: Options Outstanding, beginning (in usd per share)	$ 13.00	$ 8.31	$ 7.26
Weighted Average Exercise Price: Options granted (in usd per share)	21.31	20.15	16.37
Weighted Average Exercise Price: Options exercised (in usd per share)	7.49	4.97	6.19
Weighted Average Exercise Price: Options forfeited (in usd per share)	19.38	15.47	0.00
Weighted Average Exercise Price: Options expired (in usd per share)	0.00	0.00	11.48
Weighted Average exercise Price: Options Outstanding, ending (in usd per share)	14.78	$ 13.00	$ 8.31	$ 7.26
Weighted Average Exercise Price: Options Exercisable (in usd per share)	$ 11.16
Weighted Average Remaining Contractual Life (in years): Options Outstanding	6 years 10 months 24 days	7 years 1 month 6 days	5 years 8 months 12 days	5 years 8 months 12 days
Weighted Average Remaining Contractual Life (in years): Options Exercisable	5 years 7 months 6 days
Aggregate Intrinsic Value: Options Outstanding	$ 4,783,402	$ 4,574,680	$ 5,772,843	$ 4,663,432
Aggregate Intrinsic Value: Options Exercisable	$ 4,254,086