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Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended |
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Dec. 31, 2015 | Mar. 31, 2016
Schedule Of Accounting Policies [Line Items] |  |
Maturity period of cash and cash equivalents | Three months or less |
Scenario, Forecast [Member] |  |
Schedule Of Accounting Policies [Line Items] |  |
Unamortized deferred debt issuance costs |  | $ 3.1

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- Definition Maturity period of cash and cash equivalents. + References No definition available. + Details
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- Definition Schedule Of Accounting Policies [Line Items] + References No definition available. + Details
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- Definition The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset. + 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 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Details
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