Fair Value of Financial Instruments (Details 3) (Assets and liabilities measured at fair value on recurring basis, Contingent consideration, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011
Assets and liabilities measured at fair value on recurring basis | Contingent consideration
Fair value liabilities reconciliation of changes
Balance at the beginning of the period	$ 1,780
Issuances	1,025	1,840
Recognized gain	(1,929)	(60)
Balance at the end of the period	876	1,780
Net gain for period included in earnings attributable to contingent consideration still held at end of period	$ 1,929	$ 60