|
Stock-Based Compensation (Performance Restricted Share Activity) (Details) (Performance Shares [Member], USD $)
In Millions, except Share data in Thousands, unless otherwise specified
|
3 Months Ended |
|
Mar. 31, 2015
|
Mar. 31, 2014
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value |
$ 5.1 |
|
| Target number of shares awarded |
237 |
|
| Number of Shares |
|
|
| Outstanding at March 31, 2015 (shares) |
523 |
|
| Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized |
$ 21.3 |
|
|
Current and Future Performance Periods [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Granted |
237 |
|
| Number of Shares |
|
|
| Outstanding at December 31, 2014 (shares) |
0 |
|
| Forfeited (shares) |
(2) |
|
| Outstanding at March 31, 2015 (shares) |
235 |
|
|
Prior Performance Period [Member]
|
|
|
| Number of Shares |
|
|
| Outstanding at December 31, 2014 (shares) |
306 |
|
| Achieved (shares) |
138 |
|
| Released (shares) |
(136) |
|
| Forfeited (shares) |
(20) |
|
| Outstanding at March 31, 2015 (shares) |
288 |
|
|
Current Performance Period [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Target number of shares awarded |
149 |
|
| Award vesting period |
4 years |
|
| Maximum percentage of target number of shares eligible to receive |
125.00% |
|
| Weighted average grant date fair value per share (usd per share) |
$ 43.06 |
|
|
Future Performance Period (3 years) [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Target number of shares awarded |
88 |
|
| Award vesting period |
3 years |
|
| Maximum percentage of target number of shares eligible to receive |
188.00% |
|
| Weighted average grant date fair value per share (usd per share) |
$ 46.93 |
|
|
Prior Performance Period One [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Target number of shares awarded |
|
223 |
| Weighted average grant date fair value per share (usd per share) |
|
$ 38.25 |
| Number of Shares |
|
|
| Achieved (shares) |
|
138 |
|
Minimum [Member] | Prior Performance Period One [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Award vesting period |
|
2 years |
|
Maximum [Member] | Prior Performance Period One [Member]
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Award vesting period |
|
4 years |
| Award Recipients, Group One [Member] | Prior Performance Period One [Member] |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Maximum percentage of target number of shares eligible to receive |
|
125.00% |
| Award Recipients, Group Two [Member] | Prior Performance Period One [Member] |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
| Maximum percentage of target number of shares eligible to receive |
|
150.00% |