Equity-Based Compensation - The Director Plan Additional Information (Detail)	3 Months Ended
Mar. 31, 2015 shares
Non-Management Director Compensation Plan \| Deferred stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock issued for service during period (in shares)	4,469

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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