SUPPLEMENTAL BALANCE SHEET INFORMATION (Details) (USD $)	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Short-term Inventories
Raw materials and purchased parts	$ 65,766,000	$ 65,054,000
Work in process	18,075,000	19,257,000
Finished goods	24,887,000	28,657,000
Inventories	108,728,000	112,968,000
Long-term Inventories
Raw materials and purchased parts	4,149,000	3,306,000
Finished goods	4,926,000	6,119,000
Inventories	9,075,000	9,425,000
Property and Equipment, net
Property plant and equipment, gross	184,866,000	189,984,000
Less accumulated depreciation	(102,023,000)	(100,111,000)
Property and equipment, net	82,843,000	89,873,000
Depreciation expense, including amortization of assets under capital leases	18,200,000	13,200,000	12,400,000
Assets under capital leases, net of accumulated amortization	1,000,000	1,200,000
Accumulated amortization of capital lease assets	1,600,000	1,500,000
Land
Property and Equipment, net
Property plant and equipment, gross	3,456,000	3,544,000
Buildings
Property and Equipment, net
Property plant and equipment, gross	10,377,000	10,674,000
Leasehold improvements
Property and Equipment, net
Property plant and equipment, gross	37,591,000	35,350,000
Machinery and equipment
Property and Equipment, net
Property plant and equipment, gross	86,816,000	87,880,000
Office equipment
Property and Equipment, net
Property plant and equipment, gross	$ 46,626,000	$ 52,536,000