Equity Incentive Program - Stock Options and SSARs (Details) - USD ($)
$ / shares in Units, $ in Millions |
3 Months Ended |
Mar. 31, 2018 |
Mar. 31, 2017 |
| SSARs |
|
|
| Number of Shares [Roll Forward] |
|
|
| Beginning balance |
850,516
|
|
| Granted |
0
|
|
| Exercised |
0
|
|
| Forfeited |
0
|
|
| Expired |
(6,008)
|
|
| Ending balance |
844,508
|
|
| Exercised |
844,508
|
|
| Weighted Average Grant Date Fair Value |
|
|
| Beginning balance |
$ 21.54
|
|
| Granted |
0.00
|
|
| Exercised |
0.00
|
|
| Forfeited |
0.00
|
|
| Expired |
23.92
|
|
| Ending balance |
21.53
|
|
| Exercisable |
$ 21.53
|
|
| SARS and Options, Additional Disclosures |
|
|
| SSARs, aggregate intrinsic value, outstanding |
$ 0.0
|
|
| SSARs, aggregate intrinsic value, exercisable |
$ 0.0
|
|
| SSARs, weighted average remaining contractual terms, outstanding |
3 years 10 months
|
|
| SSARs, weighted average remaining contractual term, exercisable |
3 years 10 months
|
|
| Stock Options |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |
|
|
| Risk-free interest rate |
2.59%
|
1.93%
|
| Dividend yield |
0.00%
|
0.00%
|
| Expected life (years) |
4 years 6 months
|
4 years 6 months
|
| Volatility |
41.20%
|
38.80%
|
| Fair value at date of grant |
$ 5.39
|
|
| Stock Options, Number of Shares |
|
|
| Beginning balance |
4,901,739
|
|
| Granted |
917,717
|
|
| Exercised |
15,957
|
|
| Forfeited |
(28,366)
|
|
| Expired |
(34,715)
|
|
| Ending balance |
5,740,418
|
|
| Exercisable |
3,624,929
|
|
| Stock Options, Weighted Average Exercise Price |
|
|
| Beginning balance |
$ 18.36
|
|
| Granted |
14.29
|
|
| Exercised |
11.02
|
|
| Forfeited |
15.92
|
|
| Expired |
22.04
|
|
| Ending balance |
17.72
|
|
| Exercisable |
$ 19.46
|
|
| SARS and Options, Additional Disclosures |
|
|
| Options, aggregate intrinsic value, outstanding |
$ 2.3
|
|
| Options, aggregate intrinsic value, exercisable |
$ 1.5
|
|
| Options, weighted average remaining contractual term, outstanding |
4 years 11 months
|
|
| Options, weighted average remaining contractual term, exercisable |
4 years 1 month
|
|
| Minimum | Stock Options |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |
|
|
| Fair value at date of grant |
|
$ 6.61
|
| Maximum | Stock Options |
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |
|
|
| Fair value at date of grant |
|
$ 6.73
|