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Debt And Liquidity (Narrative) (Details) - USD ($) |  |  |  | 6 Months Ended |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 19, 2018 | Feb. 12, 2018 | Feb. 27, 2015 | Jun. 30, 2018 | Jun. 15, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Dec. 31, 2016 | Apr. 27, 2016 | Aug. 11, 2015 | Jul. 28, 2015 | Apr. 23, 2014 | Nov. 20, 2012
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | $ 2,210,006,000 |  |  | $ 339,374,000 |  | $ 365,432,000 |  |  |  |  |
Minimum Liquidity |  |  |  |  |  |  |  |  |  | $ 25,000,000 |  |  |  |
Outstanding letters of credit |  |  |  |  |  |  | $ 8,700,000 |  | 12,300,000 |  |  |  |  |
Stated interest rate |  |  |  |  |  |  | 6.375% |  |  |  |  |  |  |
Loan balance, net of unamortized discount |  |  |  | 106,378,000 |  |  | $ 16,474,000 |  | 8,852,000 |  |  |  |  |
12 Month Trailing EBITDA |  |  |  |  |  |  | 75,000,000 |  |  |  |  |  |  |
12 Month Trailing EBITDA Minimum (Low End) |  |  |  |  |  |  |  |  |  | 40,000,000 |  |  |  |
12 Month Trailing EBITDA Minimum (High End) |  |  |  |  |  |  |  |  |  | 35,000,000 |  |  |  |
Equity interest pledge |  |  |  |  |  | 65.00% |  |  |  |  |  |  |  |
Senior Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | $ 0 |  |  | $ 280,586,000 |  | 274,132,000 |  |  |  |  |
Principal amount issued |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 300,000,000
Stated interest rate |  |  |  |  |  |  | 6.375% |  |  |  |  |  |  | 6.375%
Repurchase price, percentage of principal, due to change in control |  |  |  |  |  |  |  |  |  |  |  |  |  | 101.00%
Debt Instrument, Redemption Price, Percentage |  |  |  | 101.594% |  |  |  |  |  |  |  |  |  |
Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unpaid judgment or decree in excess of |  |  |  |  |  |  | $ 50,000,000 |  |  |  |  |  |  |
Minimum | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unpaid indebtedness or accelerated proceeds exceeds |  |  |  |  |  |  |  | $ 50,000,000 |  |  |  |  |  |
Unpaid judgment or decree in excess of |  |  |  |  |  |  |  | $ 50,000,000 |  |  |  |  |  |
Amended and Restated Credit Agreement | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undrawn commitment fee |  |  | 0.35% |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Credit Agreement | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undrawn commitment fee |  |  | 0.70% |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Credit Agreement | LIBOR | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  |  | 2.25% |  |  |  |  |  |  |  |  |  |  |
Amended and Restated Credit Agreement | LIBOR | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  |  | 4.75% |  |  |  |  |  |  |  |  |  |  |
2018 Credit Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio |  |  |  |  |  | 4.00 |  |  |  |  |  |  |  |
Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Line of Credit |  |  |  | $ 0 |  |  | 58,192,000 |  | $ 90,731,000 |  |  |  |  |
Revolving Credit Facility | Amended and Restated Credit Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  |  |  |  |  |  |  |  |  |  |  |  | $ 400,000,000 |
Revolving Credit Facility | Amended and Restated Credit Agreement July 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  |  |  |  |  |  |  |  |  | $ 225,000,000 |  | $ 375,000,000 |  |
Long-term Line of Credit |  |  |  |  |  |  | 39,500,000 |  |  |  |  |  |  |
Outstanding letters of credit |  |  |  |  |  |  | 8,700,000 |  |  |  |  |  |  |
Revolving Credit Facility | 2018 Revolving Credit Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  | $ 250,000,000 |  |  | $ 2,250,000,000 | $ 1,500,000,000 |  |  |  |  |  |  |  |
Borrowing threshold (greater than) |  |  |  |  |  | $ 35,000,000 |  |  |  |  |  |  |  |
Borrowing threshold percentage |  |  |  |  |  | 35.00% |  |  |  |  |  |  |  |
Increase in borrowing capacity |  |  |  |  | $ 750,000,000 |  |  |  |  |  |  |  |  |
Debt instrument, upfront fees |  |  |  |  | 1.00% |  |  |  |  |  |  |  |  |
Revolving Credit Facility | 2018 Revolving Credit Facility | LIBO |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  | 3.75% |  |  |  |  |  |  |  |  |  |  |  |
Revolving Credit Facility | 2018 Revolving Credit Facility | ABR |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  | 2.75% |  |  |  |  |  |  |  |  |  |  |  |
Term Loan Facility | Amended and Restated Credit Agreement July 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  |  |  |  |  |  |  |  |  |  |  | $ 40,000,000 |  |
Long-term Line of Credit |  |  |  |  |  |  | $ 19,000,000 |  |  |  | $ 40,000,000 |  |  |
Line of Credit | 2018 Term Loan Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing capacity |  | $ 1,500,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  |  |  | 0.25% |  |  |  |  |  |  |  |  |  |
Debt Instrument, Amortization Rate |  |  |  |  |  | 5.00% |  |  |  |  |  |  |  |
Prepayment premium |  |  |  |  |  | 1.00% |  |  |  |  |  |  |  |
Excess Cashflow Threshold Percentage |  |  |  |  |  | 75.00% |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | Contingent Event One |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess Cashflow Threshold Percentage |  |  |  |  |  | 50.00% |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | Contingent Event Two |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Excess Cashflow Threshold Percentage |  |  |  |  |  | 0.00% |  |  |  |  |  |  |  |
Leverage ratio |  |  |  |  |  | 1.25 |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | Minimum | Contingent Event One |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio |  |  |  |  |  | 1.25 |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | Maximum | Contingent Event One |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio |  |  |  |  |  | 1.75 |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | LIBO |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  | 3.50% |  |  |  |  |  |  |  |  |  |  |  |
Undrawn commitment fee |  | 0.25% |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit | 2018 Term Loan Facility | ABR |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate |  | 2.50% |  |  |  |  |  |  |  |  |  |  |  |
Brookfield | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio | 175.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Brookfield | Brookfield Promissory Note [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends Payable | $ 750,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Brookfield | Brookfield Promissory Note [Member] | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Leverage ratio | 175.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Brookfield | Brookfield Promissory Note [Member] | LIBO |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate | 4.50% |  |  |  |  |  |  |  |  |  |  |  |  |
Third Anniversary | Brookfield | Brookfield Promissory Note [Member] | LIBO |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Margin spread on variable interest rate | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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- 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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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