CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (unaudited) - USD ($) $ in Thousands		Preferred Stock, Class A	Preferred Stock, Class B	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 (in shares) at Dec. 31, 2016			272,636	4,604,563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock grant, net of forfeiture (in shares)				26,049
Employee stock-based compensation expense					92			92
Net income						2,548		2,548
Other comprehensive income (loss)							76	76
Balance at Mar. 31, 2017			$ 3	$ 45	96,208	16,040	(89)	112,207
Balance (in shares) at Mar. 31, 2017		0	272,636	4,630,612
Balance at Dec. 31, 2017			$ 3	$ 81	211,145	25,861	(206)	236,884
Balance (in shares) at Dec. 31, 2017			272,636	8,196,310
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net	[1]				(33)			(33)
Repurchase of shares for tax withholding for restricted stock vesting					(72)			(72)
Repurchase of shares for tax withholding for restricted stock vesting (in shares)				(1,385)
Employee stock-based compensation expense					293			293
Net income						6,291		6,291
Other comprehensive income (loss)							(322)	(322)
Balance at Mar. 31, 2018			$ 3	$ 81	$ 211,333	$ 32,152	$ (528)	$ 243,041
Balance (in shares) at Mar. 31, 2018		0	272,636	8,194,925

[1] Represents costs incurred in connection with the Company's initial public offering completed in the prior period.