Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member] Voting Common Stock [Member]	Common Stock [Member] Nonvoting Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Jun. 30, 2017	0	7,840,460	991,194
Balance at Jun. 30, 2017	$ 0	$ 7,841	$ 991	$ 77,455	$ 38,142	$ (1,632)	$ 122,797
Net income					7,890		7,890
Other comprehensive income, net of tax						36	36
Conversions between voting common stock and non- voting common stock, net (in shares)		69,255	(69,255)
Conversions between voting common stock and non- voting common stock, net		$ 69	$ (69)
Dividends on common stock at $0.02 per share					(177)		(177)
Stock-based compensation				485			485
Issuance of restricted common stock (in shares)		12,000
Issuance of restricted common stock		$ 12		(12)
Cancellation and forfeiture of restricted common stock (in shares)		(15,756)
Cancellation and forfeiture of restricted common stock		$ (16)		(39)			(55)
Stock options exercised, net (in shares)		111,375
Stock options exercised, net		$ 111		(1,084)			(973)
Balance (in shares) at Dec. 31, 2017	0	8,017,334	921,939
Balance at Dec. 31, 2017	$ 0	$ 8,017	$ 922	76,805	45,855	(1,596)	130,003
Balance (in shares) at Jun. 30, 2018	0	8,056,527	882,314
Balance at Jun. 30, 2018	$ 0	$ 8,057	$ 882	77,016	54,236	(1,761)	138,430
Net income					9,659		9,659
Other comprehensive income, net of tax						33	33
Conversions between voting common stock and non- voting common stock, net (in shares)		70,368	(70,368)
Conversions between voting common stock and non- voting common stock, net		$ 70	$ (70)
Dividends on common stock at $0.02 per share					(180)		(180)
Stock-based compensation				687			687
Issuance of restricted common stock (in shares)		116,925
Issuance of restricted common stock		$ 117		(117)
Cancellation and forfeiture of restricted common stock (in shares)		(7,877)
Cancellation and forfeiture of restricted common stock		$ (8)		(126)			(134)
Stock options exercised, net (in shares)		974
Stock options exercised, net		$ 1		(5)			(4)
Adjustment for adoption of ASU 2016-01					(180)	180
Balance (in shares) at Dec. 31, 2018	0	8,236,917	811,946
Balance at Dec. 31, 2018	$ 0	$ 8,237	$ 812	$ 77,455	$ 63,535	$ (1,548)	$ 148,491