v3.8.0.1

Interest Rate Swaps - Additional Information (Detail) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($)
Derivative Instrument Detail [Abstract] |
Interest rate swaps expected to be reclassified | $ 2,401

X
- References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentDetailAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings. + References No definition available. + Details
Name: | us-gaap_DerivativeInstrumentsGainLossReclassificationFromAccumulatedOCIToIncomeEstimatedNetAmountToBeTransferred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration