Share-Based Arrangements Compensation Arrangements by Share-based Payment Award (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2012	Sep. 30, 2011	Sep. 28, 2012	Sep. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation expense	$ 1,229	$ 1,065	$ 4,809	$ 5,720
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation expense	403	351	1,474	1,385
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation expense	711	627	3,007	3,912
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation expense	0	0	0	179
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based compensation expense	$ 115	$ 87	$ 328	$ 244