Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Balance at the beginning of the year at Sep. 27, 2014	$ 258,127	$ 3,795	$ 6,112	$ 242,396	$ 5,824
Balance at the beginning of the year ( in shares) at Sep. 27, 2014		15,180
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	34,061			45,462	(11,401)
Exercise of stock options	$ 3,927	$ 23	3,904
Exercise of stock options (in shares)	92	92
Stock-based compensation	$ 7,457	$ 14	7,443
Stock-based compensation (in shares)		57
Tax benefit (shortfall) from equity compensation	734		734
Issuance for employee stock purchase plan	920	$ 4	916
Issuance for employee stock purchase plan (in shares)		16
Common stock purchased and retired	(29,115)	$ (103)	(14,834)	(14,178)
Common stock purchased and retired (in shares)		(413)
Dividends, $1.20 per share	(17,969)			(17,969)
Balance at the end of the year at Oct. 03, 2015	258,142	$ 3,733	4,275	255,711	(5,577)
Balance at the end of the year (in shares) at Oct. 03, 2015		14,932
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	22,698			27,494	(4,796)
Issuance of common stock, net of issuance costs	74,301	$ 474	73,827
Issuance of common stock, net of issuance costs (in shares)		1,897
Issuance of tangible equity units, net of issuance costs	84,511		84,511
Purchase of capped calls	(7,935)		(7,935)
Exercise of stock options	$ 2,799	$ 17	2,782
Exercise of stock options (in shares)	68	68
Stock-based compensation	$ 7,156	$ 12	7,144
Stock-based compensation (in shares)		47
Tax benefit (shortfall) from equity compensation	(172)		(172)
Issuance for employee stock purchase plan	1,048	$ 6	1,042
Issuance for employee stock purchase plan (in shares)		24
Common stock purchased and retired	(18,414)	$ (77)	(10,595)	(7,742)
Common stock purchased and retired (in shares)		(308)
Dividends, $1.20 per share	(18,874)			(18,874)
Balance at the end of the year at Oct. 01, 2016	405,260	$ 4,165	154,879	256,589	(10,373)
Balance at the end of the year (in shares) at Oct. 01, 2016		16,660
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income	34,904			25,084	9,820
Conversion of tangible equity units	0	$ 235	(235)
Settlement of tangible equity units (in shares)		939
Settlement of capped calls	$ 0	$ (3)	3
Settlement of capped calls (in shares)	12	(12)
Exercise of stock options	$ 4,559	$ 28	4,531
Exercise of stock options (in shares)	112	112
Stock-based compensation	$ 5,620	$ 17	5,603
Stock-based compensation (in shares)		69
Tax benefit (shortfall) from equity compensation	(386)		(386)
Issuance for employee stock purchase plan	1,020	$ 6	1,014
Issuance for employee stock purchase plan (in shares)		25
Common stock purchased and retired	(1,785)	$ (8)	(1,777)
Common stock purchased and retired (in shares)		(33)
Dividends, $1.20 per share	(20,415)			(20,415)
Balance at the end of the year at Sep. 30, 2017	$ 428,777	$ 4,440	$ 163,632	$ 261,258	$ (553)
Balance at the end of the year (in shares) at Sep. 30, 2017		17,760