Stock-based compensation (Details) (USD $)	12 Months Ended
	Dec. 30, 2011	Dec. 31, 2010	Dec. 25, 2009
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Income tax benefit		$ (646,000)	$ (506,000)
Total after-tax stock based compensation expense	1,823,000	1,200,000	940,000
Restricted Stock Units activity [Abstract]
Opening nonvested at beginning of period (in shares)	420,000	330,000
Ending nonvested at end of period (in shares)	580,000	420,000	330,000
Stock Options Shares [Abstract]
Opening stock options outstanding (in shares)	157,000	82,000
Ending stock options outstanding as of end of period (in shares)	1,252,000	157,000	82,000
Chief Executive Officer [Member] | Employee Stock Option [Member]
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Common shares issued to CEO for relocation expenses reimbursement	153,996
Expense in connection with share issuances	400,000
Expense recorded for bonus due to the CEO	300,000
Restricted Stock [Member]
Restricted Stock Units activity [Abstract]
Opening nonvested at beginning of period (in shares)	420,000	330,000	208,000
Granted (in shares)	369,000	238,000	223,000
Vested (in shares)	(112,000)	(123,000)	(75,000)
Forfeited/cancelled (in shares)	(97,000)	(25,000)	(26,000)
Ending nonvested at end of period (in shares)	580,000	420,000	330,000
Restricted Stock Units - Weighted Average Stock Grant Price [Abstract]
Opening nonvested restricted stock (in dollars per share)	$ 6.69	$ 11.92	$ 24.59
Granted (in dollars per share)	$ 3.47	$ 3.76	$ 6.11
Vested (in dollars per share)	$ 11.77	$ 15.03	$ 24.13
Forfeited/cancelled (in dollars per share)	$ 4.87	$ 5.80	$ 15.62
Ending nonvested at end of period (in dollars per share)	$ 3.97	$ 6.69	$ 11.92
Vesting period (in years)	Three years
Total unrecognized compensation cost related to restricted stock grants	1,400,000
Unrecognized compensation expected weighted-average recognition period (in years)	2.3
Vesting period (in years)	Three years
Stock Options [Member]
Restricted Stock Units - Weighted Average Stock Grant Price [Abstract]
Vesting period (in years)	Four years
Total unrecognized compensation cost related to restricted stock grants	2,600,000
Options expiration period (in years)	Seven years
Vesting period (in years)	Four years
Stock Options Shares [Abstract]
Opening stock options outstanding (in shares)	157,000	82,000	125,000
Granted (in shares)	1,269,000	480,000	0
Exercised (in shares)	(1,000)	0	0
Forfeited/cancelled (in shares)	(173,000)	(405,000)	(43,000)
Ending stock options outstanding as of end of period (in shares)	1,252,000	157,000	82,000
Ending stock options exercisable (in shares)	16,000	38,000	82,000
Stock Options - Weighted Average Option Grant Price [Abstract]
Opening stock options outstanding (in dollars per share)	$ 7.41	$ 17.53	$ 17.99
Granted (in dollars per share)	$ 4.66	$ 4.97	$ 0.00
Exercised (in dollars per share)	$ 3.72	$ 0	$ 0.00
Forfeited/cancelled (in dollars per share)	$ 7.25	$ 6.58	$ 18.90
Ending stock options outstanding (in dollars per share)	$ 4.64	$ 7.41	$ 17.53
Ending stock options exercisable (in dollars per share)	$ 4.75	$ 16.55	$ 17.53
Stock Options -Aggregate Intrinsic Value [Abstract]
Outstanding as of end of period	20,000	0	0
Exercisable at end of period	0	0	0
Weighted average fair value of stock options granted (in dollars per share)	$ 2.58
Weighted average assumptions based on date of grant [Abstract]
Dividend yield (in hundredths)	1.40%	2.00%
Volatility (in hundredths)	80.40%	76.60%
Risk-free interest rate (in hundredths)	1.70%	2.10%
Expected life (years)	4.8	4.8
Exercise prices of the options outstanding, minimum (in dollars per share)	$ 2.74
Exercise prices of the options outstanding, maximum (in dollars per share)	$ 6.15
Selling, General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation expense	1,639,000	1,846,000	1,446,000
Restricted Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation expense	1,054,000	1,833,000	1,446,000
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock based compensation expense	769,000	13,000	0
Severance, impairment and other associated costs	$ 184,000	$ 0	$ 0