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Shareholders' Equity, Stock Options and Net Income per Share - Stock Option Activity (Details) (USD $)
In Thousands, except Share data, unless otherwise specified |
12 Months Ended | 12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
Dec. 31, 2011
Employee Stock Option [Member]
|
Dec. 31, 2010
Employee Stock Option [Member]
|
Dec. 31, 2009
Employee Stock Option [Member]
|
Dec. 31, 2011
Non-employee Director Stock Options [Member]
|
Dec. 31, 2010
Non-employee Director Stock Options [Member]
|
Dec. 31, 2008
Non-employee Director Stock Options [Member]
|
Dec. 31, 2011
Exercise Price Range 13.25 thru 18.82 [Member]
Employee Stock Option [Member]
Years
|
Dec. 31, 2011
Exercise Price Range 20.21 thru 29.44 [Member]
Employee Stock Option [Member]
Years
|
Dec. 31, 2011
Exercise Price Range 30.35 thru 35.53 [Member]
Employee Stock Option [Member]
Years
|
Dec. 31, 2011
Exercise Price Range 13.25 thru 35.53 [Member]
Employee Stock Option [Member]
Years
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||||||||
| Outstanding at beginning of year (shares) | 3,702,000 | 3,086,000 | 2,446,000 | 63,000 | 74,000 | 74,000 | |||||||
| Granted (shares) | 117,000 | 664,000 | 675,000 | ||||||||||
| Exercise of stock options (in shares) | (451,000) | (35,000) | (1,000) | (22,000) | (11,000) | ||||||||
| Forfeited (shares) | (5,000) | (13,000) | (34,000) | ||||||||||
| Outstanding at end of year (shares) | 3,363,000 | 3,702,000 | 3,086,000 | 41,000 | 63,000 | 74,000 | 263,000 | 2,297,000 | 803,000 | 3,363,000 | |||
| Outstanding at beginning of year (per share) | $ 26 | $ 26 | $ 28 | $ 22 | $ 22 | $ 22 | |||||||
| Weighted average exercise price for options granted in the period | $ 29 | $ 22 | $ 23 | ||||||||||
| Weighted average exercise price for options exercised in the period | $ 23 | $ 21 | $ 18 | $ 23 | $ 24 | ||||||||
| Weighted average exercise price for options forfeited in the period | $ 24 | $ 26 | $ 28 | ||||||||||
| Outstanding at end of year (per share) | $ 26 | $ 26 | $ 26 | $ 21 | $ 22 | $ 22 | $ 15.08 | $ 25.78 | $ 31.37 | $ 26.28 | |||
| Exercisable at end of year | 2,585,000 | 2,475,000 | 1,906,000 | 263,000 | 1,519,000 | 803,000 | 2,585,000 | ||||||
| Weighted average exercise price for options exercisable at year end | $ 27 | $ 27 | $ 27 | $ 15.08 | $ 26.95 | $ 31.37 | $ 27.12 | ||||||
| Shares available for grant | 1,433,000 | 1,713,000 | 2,363,000 | ||||||||||
| Weighted-average fair value of options granted during the year (dollars per share) | $ 10.68 | $ 8.24 | $ 7.96 | ||||||||||
| Aggregate intrinsic value of options exercised | $ 3,771 | $ 268 | $ 3 | $ 202 | $ 37 | ||||||||
| Average aggregate intrinsic value for options outstanding | 14,169 | ||||||||||||
| Average aggregate instrinsic value for exercisable options | 8,717 | ||||||||||||
| Range of exercise price, lower range limit | $ 13.25 | $ 20.21 | $ 30.35 | $ 13.25 | |||||||||
| Range of exercise price, upper range limit | $ 18.82 | $ 29.44 | $ 35.53 | $ 35.53 | |||||||||
| Weighted average remaining contractual life | 1.4 | 4.0 | 2.4 | 3.4 | |||||||||
| Share-based compensation | 5,971 | 6,284 | 6,754 | 3,981 | 5,689 | 5,832 | |||||||
| Tax benefit related to share-based compensation expense | 1,042 | 1,707 | 1,691 | ||||||||||
| Unrecognized compensation cost | 2,810 | ||||||||||||
| Average aggregate intrinsic value for options outstanding and exercisable | $ 385 | ||||||||||||
| Non-employee Director Activity - Options [Abstract] | |||||||||||||
| Weighted average remaining contractual term for options outstanding | 2.5 | ||||||||||||
| Term of options issued under the plan | 7 | 10 | |||||||||||