XML 43 R40.htm IDEA: XBRL DOCUMENT v2.4.1.9
Notes Payable - Components of Notes Payable (Parenthetical) (Detail) (Senior Notes [Member])
 12 Months Ended
Dec. 31, 2014
Apr. 21, 2011
Mar. 17, 2014
4.03% senior notes due in 2018 [Member]
      
Debt Instrument [Line Items]      
Senior Notes, interest rate 4.03%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= mgrc_FourPointZeroThreePercentDueTwoThousandEighteenMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 4.03%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= mgrc_FourPointZeroThreePercentDueTwoThousandEighteenMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		  
Senior Notes, year of maturity 2018    
3.68% senior notes due in 2021 [Member]
      
Debt Instrument [Line Items]      
Senior Notes, interest rate 3.68%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= mgrc_ThreePointSixEightPercentDueTwoThousandTwentyOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		   3.68%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= mgrc_ThreePointSixEightPercentDueTwoThousandTwentyOneMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Senior Notes, year of maturity 2021