Stock-based compensation (Details) (USD $)
In Thousands, except Share data, unless otherwise specified |
3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 9 Months Ended | |||||||||||
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Sep. 27, 2014
|
Sep. 28, 2013
|
Sep. 27, 2014
|
Sep. 28, 2013
|
Sep. 27, 2014
Stock Options [Member]
|
Sep. 28, 2013
Stock Options [Member]
|
Sep. 27, 2014
Stock Options [Member]
|
Sep. 28, 2013
Stock Options [Member]
|
Sep. 27, 2014
Restricted Stock Units (RSUs) [Member]
|
Sep. 28, 2013
Restricted Stock Units (RSUs) [Member]
|
Sep. 27, 2014
Restricted Stock Units (RSUs) [Member]
|
Sep. 28, 2013
Restricted Stock Units (RSUs) [Member]
|
May 09, 2012
2012 Long-term Incentive Plan [Member]
Maximum [Member]
|
Sep. 27, 2014
2007 Incentive Plan [Member]
|
Sep. 27, 2014
2007 Incentive Plan [Member]
Maximum [Member]
Stock Options [Member]
|
Sep. 27, 2014
2007 Incentive Plan [Member]
Maximum [Member]
Restricted Stock Units (RSUs) [Member]
|
Sep. 27, 2014
2007 Incentive Plan [Member]
Minimum [Member]
Stock Options [Member]
|
Sep. 27, 2014
2007 Incentive Plan [Member]
Minimum [Member]
Restricted Stock Units (RSUs) [Member]
|
|
Share Based Compensation Arrangement by Share Based Payment Award [Line Items] | ||||||||||||||||||
Number of common stock reserved for issuance (shares) | 3,200,000 | |||||||||||||||||
Expiration year of 2007 Plan | Dec. 31, 2022 | |||||||||||||||||
Vesting period | 5 years | 5 years | 3 years | 3 years | ||||||||||||||
Number of options granted in period | 0 | 0 | 0 | 0 | 0 | |||||||||||||
Option awards contractual term (years) | 10 years | |||||||||||||||||
Recognized stock-based compensation costs | $ 191 | $ 251 | $ 666 | $ 1,107 | $ 7,119 | $ 4,085 | $ 20,831 | $ 12,727 | ||||||||||
Recognized stock-based compensation costs, net of tax | 121 | 159 | 422 | 701 | 4,510 | 2,588 | 13,196 | 8,063 | ||||||||||
Pre-tax unrecognized compensation expense | $ 404 | $ 404 | $ 35,753 | $ 35,753 | ||||||||||||||
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 7 months 28 days | |||||||||||||||||
Number of restricted stock units granted | 2,000 | 189,000 | 301,000 | |||||||||||||||
Weighted-average grant-date fair value (in usd per share) | $ 115.79 | $ 144.75 | $ 110.14 | |||||||||||||||
Recognized expense over a weighted-average period (years) | 2 years 2 months 12 days |