Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total		Stock Options	Number of Shares	Number of Shares Stock Options	Unearned  Shares Issued to ESOP	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at beginning of period (in shares) at Sep. 30, 2018				7,401,177
Balance at beginning of period at Sep. 30, 2018	$ 124,657			$ 14,394		$ (133)	$ 110,525	$ (129)	[1]
Balance at beginning of period (in shares) at Sep. 30, 2018				7,401,177
Balance at beginning of period at Sep. 30, 2018	124,657			$ 14,394		(133)	110,525	(129)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,685						17,685
Other comprehensive income (loss)	33							33
Repurchase of common stock (in shares)				(2,831)
Repurchase of common stock	$ (70)			$ (70)
Exercise of stock options (in shares)	37,756			37,756
Exercise of stock options	$ 340			$ 340
Common stock dividends	(5,243)						(5,243)
Earned ESOP shares, net of income taxes	441			$ 308		133
Stock option compensation expense			$ 159		$ 159
Common stock issued for business combination (in shares)				904,826
Common stock issued for business combination	28,267			$ 28,267
Balance at end of period (in shares) at Jun. 30, 2019				8,340,928
Balance at end of period at Jun. 30, 2019	166,269			$ 43,398		0	122,904	(33)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of Accounting Standards Update ("ASU") 2016-01							(63)	63
Adoption of Accounting Standards Update ("ASU") 2016-01 | Accounting Standards Update 2016-01							(63)
Balance at beginning of period (in shares) at Mar. 31, 2019				8,336,419
Balance at beginning of period at Mar. 31, 2019	162,338			$ 43,351			119,032	(45)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,956						5,956
Other comprehensive income (loss)	12							12
Repurchase of common stock (in shares)				(2,831)
Repurchase of common stock	(70)			$ (70)
Exercise of stock options (in shares)				7,340
Exercise of stock options	57			$ 57
Common stock dividends	(2,084)						(2,084)
Earned ESOP shares, net of income taxes	7			$ 7
Stock option compensation expense			53		53
Balance at end of period (in shares) at Jun. 30, 2019				8,340,928
Balance at end of period at Jun. 30, 2019	166,269			$ 43,398		0	122,904	(33)	[1]
Balance at beginning of period (in shares) at Sep. 30, 2019				8,329,419
Balance at beginning of period at Sep. 30, 2019	171,067	[2]		$ 43,030		0	127,987	50	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,912						17,912
Other comprehensive income (loss)	(74)							(74)
Repurchase of common stock (in shares)				(56,601)
Repurchase of common stock	$ (1,238)			$ (1,238)
Exercise of stock options (in shares)	37,975			37,975
Exercise of stock options	$ 391			$ 391
Common stock dividends	(5,421)						(5,421)
Earned ESOP shares, net of income taxes	31			$ 31
Stock option compensation expense			138		138
Balance at end of period (in shares) at Jun. 30, 2020				8,310,793
Balance at end of period at Jun. 30, 2020	182,806			$ 42,352		0	140,478	(24)	[1]
Balance at beginning of period (in shares) at Mar. 31, 2020				8,309,193
Balance at beginning of period at Mar. 31, 2020	178,008			$ 42,258			135,929	(179)	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,211						6,211
Other comprehensive income (loss)	155							155
Exercise of stock options (in shares)				1,600
Exercise of stock options	17			$ 17
Common stock dividends	(1,662)						(1,662)
Earned ESOP shares, net of income taxes	31			$ 31
Stock option compensation expense			$ 46		$ 46
Balance at end of period (in shares) at Jun. 30, 2020				8,310,793
Balance at end of period at Jun. 30, 2020	$ 182,806			$ 42,352		$ 0	$ 140,478	$ (24)	[1]

[1] All amounts are net of income taxes.

[2] Derived from audited consolidated financial statements.