XML 56 R43.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Notes Payable - Schedule of Information Related to Lines of Credit (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015
Debt Disclosure [Abstract] |  |
Maximum amount outstanding | $ 239,820 | $ 295,588
Average amount outstanding | $ 214,446 | $ 236,860
Weighted average interest rate, during the period | 2.19% | 2.35%
Prime interest rate, end of period | 3.75% | 3.50%

X
- Definition Line of credit facility base interest rate at period end. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityBaseInterestRateAtPeriodEnd
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility weighted interest rate during period. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityWeightedInterestRateDuringPeriod
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Average amount borrowed under the credit facility during the period. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityAverageOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Maximum amount borrowed under the credit facility at any time during the period. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityMaximumAmountOutstandingDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration