Stock-based compensation plans (Details) (USD $)	3 Months Ended		9 Months Ended			12 Months Ended	3 Months Ended		9 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]	Jun. 28, 2014 Restricted Stock [Member] Employee	Dec. 28, 2013 Restricted Stock [Member] Employee	Jun. 28, 2014 Restricted Stock [Member]	Jun. 28, 2014 1996 Equity Incentive Plan [Member]	Jun. 29, 2013 1996 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved and available for grant (in shares)										183,400	137,000
Increase in shares reserved and available for grant (in shares)										150,000
Options grants (in shares)										0	0
Options exercised (in shares)										0	0
Shares under Option [Roll Forward]
Outstanding, beginning of period (in shares)					5,000
Cancelled (in shares)					(5,000)
Outstanding, end of period (in shares)					0	5,000
Exercisable, end of period (in shares)					0
Exercisable and expected to vest, end of period (in shares)					0
Weighted average Exercise Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)					$ 5.40
Cancelled (in dollars per share)					$ 5.40
Outstanding, end of period (in dollars per share)					$ 0	$ 5.40
Exercisable, end of period (in dollars per share)					$ 0
Exercisable and expected to vest, end of period (in dollars per share)					$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual life, outstanding, beginning of period					0 years	0 years 1 month 6 days
Weighted average remaining contractual life, outstanding, end of period					0 years	0 years 1 month 6 days
Weighted average remaining contractual life, exercisable, end of period					0 years
Weighted average remaining contractual life, exercisable and expected to vest, end of period					0 years
Aggregate intrinsic value, outstanding, beginning of period					$ 0
Aggregate intrinsic value, outstanding, end of period					0	0
Aggregate intrinsic value, exercisable, end of period					0
Aggregate intrinsic value, exercisable and expected to vest, end of period					0
Number of shares of Restricted Stock [Roll Forward]
Non-vested balance, beginning of period (in shares)								103,800	103,800
Granted (in shares)							28,600	80,000	108,600
Vested (in shares)									(43,800)
Non-vested balance, end of period (in shares)							168,600		168,600
Weighted Average Grant-Date Fair Value [Roll Forward]
Non-vested balance, beginning of period (in dollars per share)								$ 5.05	$ 5.05
Granted (in dollars per share)									$ 5.23
Vested (in dollars per share)									$ 4.63
Non-vested balance, ending of period (in dollars per share)							$ 5.27		$ 5.27
Number of employees and non-employee directors with restricted stock grant							11	7
Estimated fair value of stock at date of grant							213,000	354,000
Period for recognition of unearned compensation							12 months	5 years
Charge to income for restricted stock							18,000	35,000
Quarterly charge to income for restricted stock							53,000	18,000
Stock based compensation expense	98,000	47,000	225,000	215,000
Unrecognized compensation expense	$ 716,000		$ 716,000
Weighted average period for unrecognized compensation expense to be recognized			3 years