Business Segment and Geographical Information - Revenues and Assets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 02, 2016	Oct. 03, 2015	Jul. 04, 2015	Apr. 04, 2015	Jan. 03, 2015	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Jan. 02, 2016	Jan. 03, 2015	Dec. 28, 2013
Revenues by Product Line:
Revenues	$ 107,600	$ 91,929	$ 98,327	$ 92,251	$ 105,206	$ 98,719	$ 104,835	$ 93,367	$ 390,107	$ 402,127	$ 344,499
Income from Continuing Operations Before Provision for Income Taxes:
Income from Continuing Operations Before Provision for Income Taxes									49,371	41,518	33,026
Total operating income									50,119	42,086	33,303
Interest expense, net									(748)	(568)	(277)
Total Assets:
Total Assets from Continuing Operations	415,483				413,631				415,483	413,631	442,024
Total Assets from Discontinued Operation	15				116				15	116	144
Total Assets	415,498				413,747				415,498	413,747	442,168
Depreciation and Amortization:
Depreciation and amortization									10,821	11,189	9,775
Capital Expenditures:
Capital expenditures									5,479	6,755	6,261
Long-lived assets	42,293				44,965				42,293	44,965	44,885
Export Revenues Included in United States Revenues Above									11,065	6,508	9,685
United States
Revenues by Product Line:
Revenues									193,383	174,003	129,131
Capital Expenditures:
Long-lived assets	17,373				15,685				17,373	15,685	14,118
China
Revenues by Product Line:
Revenues									50,814	43,867	50,678
Capital Expenditures:
Long-lived assets	12,278				13,996				12,278	13,996	14,603
Other
Revenues by Product Line:
Revenues									145,910	184,257	164,690
Capital Expenditures:
Long-lived assets	12,642				15,284				12,642	15,284	16,164
Operating Segments | Papermaking Systems Segment
Revenues by Product Line:
Revenues									342,661	348,199	328,708
Income from Continuing Operations Before Provision for Income Taxes:
Income from Continuing Operations Before Provision for Income Taxes									56,789	50,485	47,144
Total Assets:
Total Assets from Continuing Operations	354,417				343,937				354,417	343,937	364,102
Depreciation and Amortization:
Depreciation and amortization									7,898	7,724	8,434
Capital Expenditures:
Capital expenditures									4,639	5,640	5,843
Operating Segments | Papermaking Systems Segment | Stock-Preparation
Revenues by Product Line:
Revenues									148,341	127,496	122,704
Operating Segments | Papermaking Systems Segment | Doctoring, Cleaning, & Filtration
Revenues by Product Line:
Revenues									101,523	117,389	112,600
Operating Segments | Papermaking Systems Segment | Fluid-Handling
Revenues by Product Line:
Revenues									92,797	103,314	93,404
Operating Segments | Wood Processing Systems
Revenues by Product Line:
Revenues									36,387	41,647	4,573
Income from Continuing Operations Before Provision for Income Taxes:
Income from Continuing Operations Before Provision for Income Taxes									10,926	6,977	(382)
Total Assets:
Total Assets from Continuing Operations	53,347				55,634				53,347	55,634	63,493
Depreciation and Amortization:
Depreciation and amortization									2,384	2,977	850
Corporate and Fiber-based Products
Income from Continuing Operations Before Provision for Income Taxes:
Income from Continuing Operations Before Provision for Income Taxes									(17,596)	(15,376)	(13,459)
Total Assets:
Total Assets from Continuing Operations	$ 7,719				$ 14,060				7,719	14,060	14,429
Depreciation and Amortization:
Depreciation and amortization									539	488	491
Capital Expenditures:
Capital expenditures									840	1,115	418
Corporate and Fiber-based Products | Fiber-based Products
Revenues by Product Line:
Revenues									$ 11,059	$ 12,281	$ 11,218