| **Long-term Debt - Textual (Details) (USD $)In Millions, unless otherwise specified** |        | 3 Months Ended |        |        |        | 0 Months Ended |          |        |        |        |        |          |        |        | 1 Months Ended |        |         |        | 3 Months Ended |
|---------------------------------------------------------------------------------------|--------|----------------|--------|--------|--------|----------------|----------|--------|--------|--------|--------|----------|--------|--------|----------------|--------|---------|--------|----------------|
||
| **Long Term Debt (Textual) [ Abstract]**                                              |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    |   |           |   |
| Debt issuance, face amount                                                            |   |           |   |   |   |           |     |   |   |   |   | $ 175    |   |   |           |   |    |   |           |   |
| Senior Note, issue price                                                              |   |           |   |   |   |           |     |   |   |   |   | 103.625% |   |   |           |   |    |   |           |   |
| Senior Notes, proceeds from public offering                                           |   |           |   |   |   |           |     |   |   |   |   | 182      |   |   |           |   |    |   |           |   |
| Term loan facility, maximum borrowing capacity                                        |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 150    |           |   |
| Revolving credit facility, maximum borrowing capacity                                 |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 600    |           |   |
| Senior secured leverage ratio maximum                                                 | 1.75   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 1.75   | 1.50           |   |
| Capital expenditures, permitted                                                       |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 300    | 250            |   |
| Capital expenditures, permitted, increase                                             |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 300    | 250            |   |
| Debt instrument, basis spread on variable rate                                        |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    |   |           | 1.75% |
| Percentage owed, principal outstanding, term loan                                     |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    | 1.25%  |           |   |
| Term loan facility, draw                                                              |   |           | 75     |   |   |           |     |   |   |   |   |     |   |   |           |   |    |   |           |   |
| Senior Note, redemption price                                                         |   |           |   |   |   |           | 103.625% |   |   |   |   |     |   |   |           |   | 103.00% |   |           |   |
| Repayments of Long-term Debt                                                          |   |           |   |   |   | 281            |     |   |   |   |   |     |   |   |           | 26     |    |   |           |   |
| Senior Notes, retired                                                                 |   |           |   | 272.3  | 272.4  |           | 271.0    | 286.9  | 286.6  |   | 456.3  |     | 275.0  | 252.4  | 252.5          |   |    |   |           |   |
| Oustanding principal amount of Senior Notes to be redeemed                            |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   | 25      |   |           |   |
| Senior Notes, repurchase amount, any twelve-month period                              |   |           |   |   |   |           |     |   |   |   |   |     |   |   |           |   | 10.00%  |   |           |   |
| Loss on extinguishment of debt                                                        |   | $ 13           |   |   |   |           |     |   |   |   |   |     |   |   |           |   |    |   |           |   |
| Debt Instrument, Interest Rate, Stated Percentage                                     |   |           |   | 7.25%  |   |           |     | 8.125% |   | 2.00%  | 5.75%  |     |   | 7.75%  |           |   |    |   |           |   |

| X                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total amount of capital expenditures permitted annually.
+ References
No definition available.
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| X                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Oustanding principal amount of Senior Notes to be redeemed
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Percentage owed on principal amount outstanding for amounts drawn under the term loan facility.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Par value of debt instrument issued plus or minus a premium or a discount.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of cash received by the Company from a debt issuance of Senior Notes to the public.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Price expressed as a percentage of principal amount at which the Company may redeem its senior notes during a specific time period in the future.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The maximum amount (expressed as a percentage of outstanding principal) of the Company's Senior Notes that may be redeemed during any twelve-month period.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Max senior secured leverage ratio to permit unlimited restricted payments under credit agreement.
+ References
No definition available.
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| X                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amounts drawn on term loan facility.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum borrowing capacity under the term loan facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Percentage points added to the reference rate to compute the variable rate on the debt instrument.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Face (par) amount of debt instrument at time of issuance.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.
+ References
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