Consolidated Statements of Shareholders’ Equity - USD ($) $ in Thousands	Common Stock Common Stock Offering	Common Stock IPO	Common Stock	Preferred Stock Private Placement	Preferred Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Private Placement	Common Stock Offering	IPO	Total
Balance at beginning of the period at Dec. 31, 2014			$ 16,120			$ 94,210	$ (193)				$ 110,137
Balance at beginning of the period (in shares) at Dec. 31, 2014			20,703,700
Condensed Consolidated Statements of Shareholders’ Equity
Net income						28,383					28,383
Issuance of stock, net of offering expenses	$ 3,941			$ 10,000				$ 10,000	$ 3,941
Issuance of stock, net of offering expenses (in shares)	407,500			10,000
Dividends on common stock, $0.20 per share						(4,222)					(4,222)
Other comprehensive loss							(39)				(39)
Balance at end of the period at Dec. 31, 2015			$ 20,061		$ 10,000	118,371	(232)				148,200
Balance at end of the period (in shares) at Dec. 31, 2015			21,111,200		10,000
Condensed Consolidated Statements of Shareholders’ Equity
Net income						33,127					33,127
Issuance of stock, net of offering expenses				$ 31,581				$ 31,581
Issuance of stock, net of offering expenses (in shares)				31,625
Dividends on preferred stock						(2,002)					(2,002)
Dividends on common stock, $0.20 per share						(4,222)					(4,222)
Other comprehensive loss							(396)				(396)
Balance at end of the period at Dec. 31, 2016			$ 20,061		$ 41,581	145,274	(628)				206,288
Balance at end of the period (in shares) at Dec. 31, 2016			21,111,200		41,625
Condensed Consolidated Statements of Shareholders’ Equity
Net income						54,684					54,684
Issuance of stock, net of offering expenses		$ 106,245								$ 106,245
Issuance of stock, net of offering expenses (in shares)		7,187,500
Shares issued for stock compensation plan (in shares)			3,200
Compensation expense for stock compensation plan			$ 458								458
Cash paid in lieu of fractional shares in stock split			(4)
Shares issued for Richmac acquisition			$ 8,127								8,127
Shares issued for Richmac acquisition (in shares)			383,271
Dividends on preferred stock						(3,330)					(3,330)
Dividends on common stock, $0.20 per share						(4,620)					(4,620)
Other comprehensive loss							(378)				(378)
Balance at end of the period at Dec. 31, 2017			$ 134,891		$ 41,581	$ 192,008	$ (1,006)				$ 367,474
Balance at end of the period (in shares) at Dec. 31, 2017			28,685,167		41,625