Condensed Consolidated Statements of Comprehensive Earnings - Unaudited (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Condensed Consolidated Statements of Comprehensive Earnings [Abstract]
Net earnings	$ 3,568	$ 2,283
Other comprehensive (loss)/earnings:
Cumulative translation adjustment, net of tax of $534 and tax benefit of $335	(1,741)	1,162
Defined benefit and post-retirement benefit plans:
Amortization of prior service cost included in net periodic pension costs, net of tax of $59 and $59	91	92
Amortization of loss included in net periodic pension costs, net of tax of $774 and $606	1,245	980
Foreign exchange impact, net of tax of $74 and tax benefit of $42	207	(114)
Reclassification adjustments included in net earnings- defined benefit and post-retirement benefit plans	1,543	958
Unrealized gain on interest swaps treated as cash flow hedges:
Unrealized holding gains arising during period, net of tax of $14	22
Reclassification adjustments for losses included in net earnings, net of tax of $30	47
Net change in unrealized holding loss on interest rate swaps	69
Other comprehensive (loss)/earnings	(129)	2,120
Comprehensive earnings	$ 3,439	$ 4,403