Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the year at Sep. 30, 2017	$ 428,777	$ 4,440	$ 163,632	$ 261,258	$ (553)
Balance at the beginning of the year (in shares) at Sep. 30, 2017		17,760
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	50,967			41,589	9,378
Exercise of stock options	212	$ 1	211
Exercise of stock options (in shares)		4
Stock-based compensation	3,178	$ 7	3,171
Stock-based compensation (in shares)		30
Issuance for employee stock purchase plan	533	$ 3	530
Issuance for employee stock purchase plan (in shares)		12
Common stock purchased and retired	(757)	$ (3)	(754)
Common stock purchased and retired (in shares)		(14)
Dividends	(10,680)			(10,680)
Balance at the end of the year at Mar. 31, 2018	472,230	$ 4,448	166,757	292,200	8,825
Balance at the end of the year (in shares) at Mar. 31, 2018		17,792
Balance at the beginning of the year at Dec. 30, 2017	461,580	$ 4,445	164,577	289,105	3,453
Balance at the beginning of the year (in shares) at Dec. 30, 2017		17,780
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	13,810			8,438	5,372
Stock-based compensation	1,663		1,663
Issuance for employee stock purchase plan	533	$ 3	530
Issuance for employee stock purchase plan (in shares)		12
Common stock purchased and retired	(13)		(13)
Dividends	(5,343)			(5,343)
Balance at the end of the year at Mar. 31, 2018	472,230	$ 4,448	166,757	292,200	8,825
Balance at the end of the year (in shares) at Mar. 31, 2018		17,792
Balance at the beginning of the year at Sep. 29, 2018	477,932	$ 4,464	171,407	300,585	1,476
Balance at the beginning of the year (in shares) at Sep. 29, 2018		17,856
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	18,567			24,661	(6,094)
Exercise of stock options	144	$ 1	143
Exercise of stock options (in shares)		3
Stock-based compensation	5,219	$ 8	5,211
Stock-based compensation (in shares)		33
Issuance for employee stock purchase plan	557	$ 4	553
Issuance for employee stock purchase plan (in shares)		16
Common stock purchased and retired	(398)	$ (2)	(396)
Common stock purchased and retired (in shares)		(8)
Dividends	(10,740)			(10,740)
Balance at the end of the year at Mar. 30, 2019	485,054	$ 4,475	176,918	308,279	(4,618)
Balance at the end of the year (in shares) at Mar. 30, 2019		17,900
Balance at the beginning of the year at Dec. 29, 2018	473,335	$ 4,468	173,065	299,493	(3,691)
Balance at the beginning of the year (in shares) at Dec. 29, 2018		17,872
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	13,233			14,160	(927)
Exercise of stock options	106	$ 1	105
Exercise of stock options (in shares)		3
Stock-based compensation	3,239	$ 2	3,237
Stock-based compensation (in shares)		10
Issuance for employee stock purchase plan	557	$ 4	553
Issuance for employee stock purchase plan (in shares)		16
Common stock purchased and retired	(42)		(42)
Common stock purchased and retired (in shares)		(1)
Dividends	(5,374)			(5,374)
Balance at the end of the year at Mar. 30, 2019	$ 485,054	$ 4,475	$ 176,918	$ 308,279	$ (4,618)
Balance at the end of the year (in shares) at Mar. 30, 2019		17,900