Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Sep. 30, 2017	19,041
Balance at Sep. 30, 2017	$ 19,041	$ 69,817	$ 135,851	$ (1,333)	$ 223,376
Net earnings			8,111		8,111
Compensation expense associated with stock-based plans		235			235
Cash dividends declared			(19,612)		(19,612)
Balance (in shares) at Dec. 30, 2017	19,041
Balance at Dec. 30, 2017	$ 19,041	70,052	124,350	(1,333)	212,110
Balance (in shares) at Sep. 30, 2017	19,041
Balance at Sep. 30, 2017	$ 19,041	69,817	135,851	(1,333)	223,376
Net earnings					26,858
Balance (in shares) at Jun. 30, 2018	19,085
Balance at Jun. 30, 2018	$ 19,085	70,982	141,953	(1,333)	230,687
Balance (in shares) at Dec. 30, 2017	19,041
Balance at Dec. 30, 2017	$ 19,041	70,052	124,350	(1,333)	212,110
Net earnings			5,879		5,879
Compensation expense associated with stock-based plans		838			838
Restricted stock units and stock options surrendered for withholding taxes payable		(210)			(210)
Cash dividends declared			(572)		(572)
Vesting of restricted stock units (in shares)	20
Vesting of restricted stock units	$ 20	(20)
Stock options exercised, net (in shares)	2
Stock options exercised, net	$ 2	(2)
Balance (in shares) at Mar. 31, 2018	19,063
Balance at Mar. 31, 2018	$ 19,063	70,658	129,657	(1,333)	218,045
Net earnings			12,868		12,868
Compensation expense associated with stock-based plans		168			168
Restricted stock units and stock options surrendered for withholding taxes payable		(64)			(64)
Cash dividends declared			(572)		(572)
Stock options exercised, net (in shares)	22
Stock options exercised, net	$ 22	220			242
Balance (in shares) at Jun. 30, 2018	19,085
Balance at Jun. 30, 2018	$ 19,085	70,982	141,953	(1,333)	230,687
Balance (in shares) at Sep. 29, 2018	19,223
Balance at Sep. 29, 2018	$ 19,223	72,852	151,084	(1,494)	241,665
Net earnings			4,126		4,126
Compensation expense associated with stock-based plans		174			174
Restricted stock units and stock options surrendered for withholding taxes payable		(7)			(7)
Cash dividends declared			(576)		(576)
Balance (in shares) at Dec. 29, 2018	19,223
Balance at Dec. 29, 2018	$ 19,223	73,019	154,634	(1,494)	245,382
Balance (in shares) at Sep. 29, 2018	19,223
Balance at Sep. 29, 2018	$ 19,223	72,852	151,084	(1,494)	241,665
Net earnings					7,365
Balance (in shares) at Jun. 29, 2019	19,252
Balance at Jun. 29, 2019	$ 19,252	73,849	156,717	(1,494)	248,324
Balance (in shares) at Dec. 29, 2018	19,223
Balance at Dec. 29, 2018	$ 19,223	73,019	154,634	(1,494)	245,382
Net earnings			1,049		1,049
Compensation expense associated with stock-based plans		845			845
Restricted stock units and stock options surrendered for withholding taxes payable		(168)			(168)
Cash dividends declared			(578)		(578)
Vesting of restricted stock units (in shares)	29
Vesting of restricted stock units	$ 29	(29)
Balance (in shares) at Mar. 30, 2019	19,252
Balance at Mar. 30, 2019	$ 19,252	73,667	155,105	(1,494)	246,530
Net earnings			2,190		2,190
Compensation expense associated with stock-based plans		182			182
Cash dividends declared			(578)		(578)
Balance (in shares) at Jun. 29, 2019	19,252
Balance at Jun. 29, 2019	$ 19,252	$ 73,849	$ 156,717	$ (1,494)	$ 248,324