Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Assets
Allowance for doubtful accounts	$ 3,070	$ 2,969
Accumulated depreciation	130,790	125,405
Accumulated amortization	$ 19,479	$ 16,941
Shareholders’ Equity:
Preferred stock, shares authorized	500	500
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	70,000	70,000
Common stock, shares issued	42,255	42,136
Common stock, shares outstanding	42,255	42,136
Common stock, no par value	$ 0	$ 0