Equity Incentive Plans (Details 1) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Jan. 01, 2012	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	1,153
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 18.90
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	6 years 9 months 15 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 10,785
Summary of the activity of stock option awards
Options outstanding, Beginning Balance , Shares	1,601
Options outstanding, Beginning Balance, Wtd. Avg. Exercise Price	$ 19.44
Options outstanding, Beginning Balance, Wtd. Avg., Remaining Contractual Term	6 years 10 months 6 days	6 years 8 months 23 days
Options outstanding, Beginning Balance, Average Intrinsic Value	2,778
Options granted, Shares	96
Options granted, Wtd. Avg. Exercise Price	$ 22.30
Options exercised, Shares	593
Options exercised, Wtd. Avg. Exercise Price	$ 15.65
Options forfeited/canceled/expired, Shares	(73)
Options forfeited/canceled/expired, Wtd. Avg. Exercise Price	$ 22.93
Options outstanding, Ending Balance , Shares	1,198	1,601
Options outstanding, Ending Balance, Wtd. Avg. Exercise Price	$ 18.92	$ 19.44
Options outstanding, Ending Balance, Wtd. Avg., Remaining Contractual Term	6 years 10 months 6 days	6 years 8 months 23 days
Options outstanding, Ending Balance, Average Intrinsic Value	11,090	2,778
Options exercisable at January 1, 2012, Shares			722
Options exercisable at January 1, 2012, Wtd. Avg. Exercise Price			$ 17.51
Options exercisable at January 1, 2012, Wtd. Avg. Remaining Contractual Term	5 years 11 months 12 days
Options exercisable at January 1, 2012, Aggregate Intrinsic Value			$ 7,694
Incremental Shares Granted due to Anti-dilution Provision	167