Earnings Per Share (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic Net Income per Common Share Available to Common Stockholders [Abstract]
Net income					$ 4,625,000	$ 7,595,000	$ 8,200,000	$ 6,264,000	$ 36,600,000	$ 26,684,000	$ 21,840,000
Preferred stock dividends									0	0	(825,000)
Net income available to common stockholders	$ 9,939,000	$ 8,234,000	$ 10,037,000	$ 8,390,000	$ 4,625,000	$ 7,595,000	$ 8,200,000	$ 6,264,000	$ 36,600,000	$ 26,684,000	$ 21,015,000
Weighted average common shares outstanding									14,487,126	12,531,659	10,149,099
Basic earnings per common share	$ 0.62	$ 0.54	$ 0.72	$ 0.66	$ 0.37	$ 0.61	$ 0.66	$ 0.50	$ 2.53	$ 2.13	$ 2.07
Diluted Net Income per Common Share Available to Common Stockholders [Abstract]
Net income available to common stockholders	$ 9,939,000	$ 8,234,000	$ 10,037,000	$ 8,390,000	$ 4,625,000	$ 7,595,000	$ 8,200,000	$ 6,264,000	$ 36,600,000	$ 26,684,000	$ 21,015,000
Effect of assumed preferred stock conversion									0	0	825,000
Net income applicable to diluted earnings per share									$ 36,600,000	$ 26,684,000	$ 21,840,000
Weighted average common shares outstanding									14,487,126	12,531,659	10,149,099
Dilutive potential common shares [Abstract]
Assumed conversion of stock options									209	4,875	3,111
Restricted stock awarded									13,250	0	4,107
Assumed conversion of preferred stock									0	0	507,393
Dilutive potential common shares									13,459	4,875	514,611
Diluted weighted average common shares outstanding									14,500,585	12,536,534	10,663,710
Diluted earnings per common share	$ 0.62	$ 0.54	$ 0.72	$ 0.66	$ 0.37	$ 0.61	$ 0.66	$ 0.50	$ 2.52	$ 2.13	$ 2.05