CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Mar. 31, 2018	$ 226	$ 64,871	$ 56,552	$ (4,748)	$ 116,901
Balance (in shares) at Mar. 31, 2018	22,570,179
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			13,059		13,059
Cash dividends on common stock			(2,485)		(2,485)
Exercise of stock options		151			$ 151
Exercise of stock options (in shares)	28,533				28,533
Stock-based compensation expense		34			$ 34
Other comprehensive income, net				434	434
Balance at Dec. 31, 2018	$ 226	65,056	67,126	(4,314)	128,094
Balance (in shares) at Dec. 31, 2018	22,598,712
Balance at Sep. 30, 2018	$ 226	65,044	63,642	(6,502)	122,410
Balance (in shares) at Sep. 30, 2018	22,598,712
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			4,388		4,388
Cash dividends on common stock			(904)		(904)
Stock-based compensation expense		12			12
Other comprehensive income, net				2,188	2,188
Balance at Dec. 31, 2018	$ 226	65,056	67,126	(4,314)	128,094
Balance (in shares) at Dec. 31, 2018	22,598,712
Balance at Mar. 31, 2019	$ 226	65,094	70,428	(2,626)	133,122
Balance (in shares) at Mar. 31, 2019	22,607,712
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			12,854		12,854
Cash dividends on common stock			(3,179)		(3,179)
Exercise of stock options	$ 1	226			$ 227
Exercise of stock options (in shares)	58,000				58,000
Restricted stock grants (in shares)	82,673
Stock-based compensation expense		317			$ 317
Other comprehensive income, net				2,465	2,465
Balance at Dec. 31, 2019	$ 227	65,637	80,103	(161)	145,806
Balance (in shares) at Dec. 31, 2019	22,748,385
Balance at Sep. 30, 2019	$ 227	65,559	77,112	221	143,119
Balance (in shares) at Sep. 30, 2019	22,748,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			4,128		4,128
Cash dividends on common stock			(1,137)		(1,137)
Exercise of stock options		10			10
Stock-based compensation expense		68			68
Other comprehensive income, net				(382)	(382)
Balance at Dec. 31, 2019	$ 227	$ 65,637	$ 80,103	$ (161)	$ 145,806
Balance (in shares) at Dec. 31, 2019	22,748,385