|
Stock-Based Compensation - Restricted Stock Units (Details) (USD $)
|
3 Months Ended |
|
Mar. 31, 2015
|
| Restricted Stock Units Time Based [Member] | LTIP Plan [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Number of restricted units granted |
297,764 |
| Number of restricted units outstanding |
741,044 |
| Restricted Stock Units Time Based [Member] | Assumed Plans [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Number of restricted units granted |
186,218 |
| Number of restricted units outstanding |
373,212 |
| Restricted Stock Units Time Based [Member] | Straight Line Vesting Basis [Member] | Minimum [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Vesting period |
2 years |
| Restricted Stock Units Time Based [Member] | Straight Line Vesting Basis [Member] | Maximum [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Vesting period |
4 years |
| Restricted Stock Units Time Based [Member] | Cliff Vesting [Member] | Minimum [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Vesting period |
3 years |
| Restricted Stock Units Time Based [Member] | Cliff Vesting [Member] | Maximum [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Vesting period |
4 years |
| Restricted Stock Units Performance Based [Member] | LTIP Plan [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Number of restricted units granted |
478,652 |
| Number of restricted units outstanding |
1,104,620 |
| Restricted Stock Units Performance Based [Member] | Assumed Plans [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Number of restricted units granted |
101,672 |
| Number of restricted units outstanding |
188,620 |
| Restricted Stock Units Performance Based [Member] | Cliff Vesting [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Vesting period |
3 years |
| Restricted Stock Units (RSUs) [Member] | LTIP Plan [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Weighted average grant date value of restricted units granted (in dollars per unit) |
49.65 |
| Weighted average grant date fair value of restricted units outstanding (in dollars per unit) |
48.34 |
| Restricted Stock Units (RSUs) [Member] | Assumed Plans [Member] |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
| Weighted average grant date value of restricted units granted (in dollars per unit) |
49.65 |
| Weighted average grant date fair value of restricted units outstanding (in dollars per unit) |
48.04 |