CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands	Class B Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI loss, Net	Total
Balance at Dec. 31, 2016	$ 3	$ 45	$ 96,116	$ 13,492	$ (165)	$ 109,491
Balance, Shares at Dec. 31, 2016	272,636	4,604,563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock, net of forfeiture			(7)			(7)
Restricted stock, net of forfeiture (in shares)		28,449
Employee stock-based compensation			313			313
Net income				9,044		9,044
Other comprehensive income (loss)					118	118
Balance, Shares at Sep. 30, 2017	272,636	4,633,012
Balance at Sep. 30, 2017	$ 3	$ 45	96,422	22,536	(47)	118,959
Balance at Dec. 31, 2017	$ 3	$ 81	211,145	25,861	(206)	$ 236,884
Balance, Shares at Dec. 31, 2017	272,636	8,196,310				8,196,310
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock, net of forfeiture			440			$ 440
Restricted stock, net of forfeiture (in shares)		8,987
Employee stock-based compensation			1,219			1,219
Exercise of stock options, net of redemption of common stock for exercise of stock options and tax withholdings for restricted stock vesting			(12)			(12)
Exercise of stock options, net of redemption of common stock for exercise of stock options and tax withholdings for restricted stock vesting		1,937
Issuance of common stock			(33)			(33)
Net income				19,268		19,268
Other comprehensive income (loss)					(497)	$ (497)
Balance, Shares at Sep. 30, 2018	272,636	8,207,234				8,207,234
Balance at Sep. 30, 2018	$ 3	$ 81	$ 212,759	$ 45,129	$ (703)	$ 257,269