Shareholders' Equity: (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended
	Jun. 21, 2011	Dec. 29, 2012	Dec. 31, 2011
Shareholders' Equity
Weighted average grant-date fair value of options granted (in dollars per share)		$ 3.57	$ 2.44
Intrinsic value
Intrinsic value related to options outstanding		$ 3.8	$ 2.3
Intrinsic value related to vested options outstanding		2.6	1.7
Closing stock price (in dollars per share)		$ 6.31	$ 3.74
Treasury Stock
Authorized amount of stock repurchase	$ 3
Stock options
Shareholders' Equity
Options Outstanding (in shares)		1,222,727
Weighted Average Remaining Contractual Life		6 years 7 months 6 days
Weighted Average Exercise Price (in dollars per share)		$ 3.26
Options Exercisable (in shares)		638,927
Weighted Average Exercise Price (in dollars per share)		$ 2.32
Stock options | Range of exercise price per share from $1.59 to $1.86
Shareholders' Equity
Exercise price, low end of range (in dollars per share)		$ 1.59
Exercise price, high end of range (in dollars per share)		$ 1.86
Options Outstanding (in shares)		406,000
Weighted Average Remaining Contractual Life		5 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)		$ 1.74
Options Exercisable (in shares)		322,500
Weighted Average Exercise Price (in dollars per share)		$ 1.74
Stock options | Range of exercise price per share from $1.94 to $3.44
Shareholders' Equity
Exercise price, low end of range (in dollars per share)		$ 1.94
Exercise price, high end of range (in dollars per share)		$ 3.44
Options Outstanding (in shares)		402,527
Weighted Average Remaining Contractual Life		5 years 6 months
Weighted Average Exercise Price (in dollars per share)		$ 2.73
Options Exercisable (in shares)		253,927
Weighted Average Exercise Price (in dollars per share)		$ 2.60
Stock options | Range of exercise price per share from $3.60 to $4.28
Shareholders' Equity
Exercise price, low end of range (in dollars per share)		$ 3.60
Exercise price, high end of range (in dollars per share)		$ 4.28
Options Outstanding (in shares)		216,700
Weighted Average Remaining Contractual Life		8 years 3 months 18 days
Weighted Average Exercise Price (in dollars per share)		$ 4.10
Options Exercisable (in shares)		62,500
Weighted Average Exercise Price (in dollars per share)		$ 4.15
Stock options | Range of exercise price per share from $6.55 to $6.55
Shareholders' Equity
Exercise price, low end of range (in dollars per share)		$ 6.55
Exercise price, high end of range (in dollars per share)		$ 6.55
Options Outstanding (in shares)		197,500
Weighted Average Remaining Contractual Life		9 years 4 months 24 days
Weighted Average Exercise Price (in dollars per share)		$ 6.55