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Shareholders' Equity (Share Repurchases) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions | 12 Months Ended
--- | ---
Dec. 26, 2018 | Dec. 27, 2017 | Dec. 28, 2016
Equity, Class of Treasury Stock [Line Items] |  |  |
Common stock shares repurchased during the period (shares) | 3.9 |  | 4.6
Common stock shares repurchased during the period (value in US$) | $ 61,189 | $ 82,858 | $ 51,771
Share Repurchase Program 2017 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase, authorized amount (dollars) | 200,000 |  |
Remaining shares to be repurchased (value in US$) | 128,400 |  |
Share Repurchase Program 2016 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase, authorized amount (dollars) |  | $ 100,000 |
Accelerated Share Repurchase 2015 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase, authorized amount (dollars) |  |  | $ 50,000
Common stock shares repurchased during the period (shares) |  |  | 1.5
Common stock shares repurchased during the period (value in US$) |  |  | $ 13,100
Volume-weighted average price |  |  | $ 9.90
Accelerated Share Repurchase 2016 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase, authorized amount (dollars) |  |  | $ 25,000
Common stock shares repurchased during the period (shares) |  | 0.5 | 1.5
Common stock shares repurchased during the period (value in US$) |  | $ 6,900 | $ 18,100
Volume-weighted average price |  | $ 12.36 |
Remaining shares to be repurchased (value in US$) |  |  | $ 6,900
Accelerated Share Repurchase 2018 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase, authorized amount (dollars) | $ 25,000 |  |
Common stock shares repurchased during the period (shares) | 1.1 |  |
Common stock shares repurchased during the period (value in US$) | $ 18,200 |  |
Remaining shares to be repurchased (value in US$) | $ 6,800 |  |

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