XML 54 R41.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Notes Payable - Additional Information (Detail) - USD ($) |  |  | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Nov. 05, 2015 | Mar. 17, 2014 | Dec. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016 | Feb. 09, 2016 | Apr. 21, 2011
Debt Instrument [Line Items] |  |  |  |  |  |  |
Consolidated Fixed Charge Coverage Ratio |  |  | 2.50% |  |  |  |
Consolidated Fixed Charge Coverage Ratio, actual |  |  | 6.82% |  |  |  |
Consolidated Leverage Ratio |  |  | 2.75% |  |  |  |
Consolidated Leverage Ratio, actual |  |  | 1.70% |  |  |  |
Line of credit facility covenants tangible net worth description |  |  | Permit Tangible Net Worth, calculated as of the last day of each fiscal quarter, to be less than the sum of (i) $229.0 million, plus (ii) 25% of net income for such fiscal quarter subsequent to December 31, 2010, plus (iii) 90% of the net cash proceeds from the issuance of the Company’s capital stock after December 31, 2010. |  |  |  |
Tangible Net Worth sum |  |  | $ 349,900,000 |  |  |  |
Consolidated Net Income |  |  | 25.00% |  |  |  |
Percentage of net cash proceeds from issuance of capital stock |  |  | 90.00% |  |  |  |
Actual tangible net worth |  |  | $ 488,700,000 |  |  |  |
Senior notes principal balance outstanding |  |  | $ 303,473,000 | $ 326,376,000 |  |  |
2016 Amendment [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Senior notes description |  |  | (i) the issuance period for the shelf notes to be issued and sold pursuant to the Note Purchase Agreement is extended until the earlier of February 9, 2019 or the termination of the issuance and sale of the shelf notes upon the 30 days’ prior notice of either PIM or the Company, and (ii) the definition of the “Available Facility Amount,” which is the aggregate amount of the shelf notes that may be authorized for purchase pursuant to the Note Purchase Agreement was amended to equal a formula based on: $250 million, minus the aggregate principal amount of the shelf notes then outstanding and purchased pursuant to the Note Purchase Agreement, minus the shelf notes accepted by the Company for purchase, but not yet purchased, by the Purchaser pursuant to the Note Purchase Agreement; provided, however, the aggregate amount of the shelf notes purchased by any corporation or other entity controlling, controlled by, or under common control with, PIM shall not exceed $200 million. |  |  |  |
Stated formula value for determining available facility amount |  |  |  |  |  | $ 250,000,000 |
Series A senior notes [Member] | 4.03% Series A senior notes due in 2018 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  |  | $ 100,000,000
Senior notes interest rate |  |  | 4.03% |  |  |  | 4.03%
Debt instrument, payment terms |  |  | Interest on these notes is due semi-annually in arrears and the principal is due in five equal annual installments, with the first payment due on April 21, 2014. |  |  |  |
Debt instrument, maturity date |  |  | Apr. 21, 2018 |  |  |  |
Debt instrument, date of first required payment |  |  | Apr. 21, 2014 |  |  |  |
Senior notes principal balance outstanding |  |  | $ 20,000,000 | 40,000,000 |  |  |
Series B Senior Notes [Member] | 3.68% Series B senior notes due in 2021 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Senior notes interest rate |  | 3.68% | 3.68% |  |  |  |
Debt instrument, maturity date |  |  | Mar. 17, 2021 |  |  |  |
Senior notes principal balance outstanding |  |  | $ 40,000,000 | 40,000,000 |  |  |
Proceeds from issuance of senior notes |  | $ 40,000,000 |  |  |  |  |
Senior notes description |  |  | The Series B Senior Notes are an unsecured obligation of the Company, bear interest at a rate of 3.68% per annum and mature on March 17, 2021. Interest on the Series B Senior Notes is payable semi-annually beginning on September 17, 2014 and continuing thereafter on March 17 and September 17 of each year until maturity. |  |  |  |
Senior notes interest payment |  |  | Semi-annually |  |  |  |
Series C Senior Notes [Member] | 3.84% Series C senior notes due in 2022 [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Senior notes interest rate | 3.84% |  | 3.84% |  |  |  |
Debt instrument, payment terms |  |  | Interest on the Series C Senior Notes is payable semi-annually beginning on May 5, 2016 and continuing thereafter on November 5 and May 5 of each year until maturity. |  |  |  |
Debt instrument, maturity date |  |  | Nov. 05, 2022 |  |  |  |
Debt instrument, date of first required payment |  |  | May 05, 2016 |  |  |  |
Senior notes principal balance outstanding |  |  | $ 60,000,000 | $ 60,000,000 |  |  |
Proceeds from issuance of senior notes | $ 60,000,000 |  |  |  |  |  |
Senior notes interest payment |  |  | Semi-annually |  |  |  |
Minimum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Tangible Net Worth sum |  |  | $ 229,000,000 |  |  |  |
Maximum [Member] | 2016 Amendment [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate principal amount |  |  |  |  |  | $ 200,000,000 |
Credit Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Revolving credit facility, maturity period |  |  | 5 years |  |  |  |
Revolving credit facility, maturity date |  |  | Mar. 31, 2021 |  |  |  |
Credit facility, maximum |  |  | $ 420,000,000 |  |  |  |
Revolving credit facility, available maximum borrowing capacity |  |  | 620,000,000 |  |  |  |
Additional commitments |  |  | $ 200,000,000 |  |  |  |
Consolidated Fixed Charge Coverage Ratio |  |  | 2.50% |  |  |  |
Consolidated Fixed Charge Coverage Ratio, actual |  |  | 6.82% |  |  |  |
Consolidated Leverage Ratio |  |  | 2.75% |  |  |  |
Consolidated Leverage Ratio, actual |  |  | 1.70% |  |  |  |
Line of credit facility covenants tangible net worth description |  |  | Permit Tangible Net Worth as of the end of any fiscal quarter of the Company to be less than the sum of (i) $246.1 million plus (ii) 25% of the Company’s Consolidated Net Income (as defined in the Amended Credit Facility) (but only if a positive number) for each fiscal quarter ended subsequent to December 31, 2011 |  |  |  |
Tangible Net Worth sum |  |  | $ 349,900,000 |  |  |  |
Consolidated Net Income |  |  | 25.00% |  |  |  |
Percentage of net cash proceeds from issuance of capital stock |  |  | 90.00% |  |  |  |
Actual tangible net worth |  |  | $ 488,700,000 |  |  |  |
Debt instrument description of variable rate basis |  |  | (i) LIBOR plus a defined margin, or (ii) the Agent bank’s prime rate (“base rate”) plus a margin. The applicable margin for each type of loan is measured based upon the Consolidated Leverage Ratio at the end of the prior fiscal quarter and ranges from 1.00% to 1.75% for LIBOR loans and 0% to 0.75% for base rate loans. In addition, the Company pays an unused commitment fee for the portion of the $420.0 million credit facility that is not used. These fees are based upon the Consolidated Leverage Ratio and range from 0.15% to 0.30%. As of December 31, 2017 and 2016, the applicable margins were 1.25% and 1.50% for LIBOR based loans, respectively, 0.25% and 0.50% for base rate loans, respectively and 0.20% and 0.25% for unused fees, respectively. Amounts borrowed under the Sweep Service Facility are based upon the MUFG Union Bank, N.A. base rate plus an applicable margin and an unused commitment fee for the portion of the $12.0 million facility not used. |  |  |  |
Unused commitment fees |  |  | $ 420,000,000 |  |  |  |
Credit Facility [Member] | Unused Fees [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt instrument interest rate at period end |  |  | 0.20% | 0.25% |  |  |
Credit Facility [Member] | LIBOR Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt instrument interest rate at period end |  |  | 1.25% | 1.50% |  |  |
Credit Facility [Member] | Base Rate Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Debt instrument interest rate at period end |  |  | 0.25% | 0.50% |  |  |
Credit Facility [Member] | Sweep Service Facility [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  | $ 432,000,000 |  |  |  |
Revolving credit facility, available maximum borrowing capacity |  |  | 248,500,000 |  |  |  |
Amount outstanding |  |  | 183,500,000 |  |  |  |
Unused commitment fees |  |  | 12,000,000 |  |  |  |
Credit Facility [Member] | Minimum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Tangible Net Worth sum |  |  | $ 246,100,000 |  |  |  |
Leverage ratio |  |  | 0.15% |  |  |  |
Credit Facility [Member] | Minimum [Member] | LIBOR Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Leverage ratio |  |  | 1.00% |  |  |  |
Credit Facility [Member] | Minimum [Member] | Base Rate Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Leverage ratio |  |  | 0.00% |  |  |  |
Credit Facility [Member] | Maximum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Leverage ratio |  |  | 0.30% |  |  |  |
Credit Facility [Member] | Maximum [Member] | LIBOR Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Leverage ratio |  |  | 1.75% |  |  |  |
Credit Facility [Member] | Maximum [Member] | Base Rate Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Leverage ratio |  |  | 0.75% |  |  |  |
Unsecured revolving credit facility before Renewal [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  | $ 420,000,000 |  |  |  |
Letters of Credit [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  | 25,000,000 |  |  |  |
Letters of Credit [Member] | Minimum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  |  |  | $ 10,000,000 |  |
Letters of Credit [Member] | Maximum [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  |  |  | $ 12,000,000 |  |
Swingline Loans [Member] |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Credit facility, maximum |  |  | $ 10,000,000 |  |  |  |

X
- Definition Actual tangible net worth. + References No definition available. + Details
Name: | mgrc_ActualTangibleNetWorth
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date when the first installment of the debt instrument is scheduled to be repaid, in CCYY-MM-DD format. + References No definition available. + Details
Name: | mgrc_DebtInstrumentRepaymentDateOne
Namespace Prefix: | mgrc_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility additional capacity available. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityAdditionalCapacityAvailable
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line of credit facility covenants actual aggregate fixed charge coverage ratio. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsActualAggregateFixedChargeCoverageRatio
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants actual aggregate fixed charge leverage ratio. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsActualAggregateFixedChargeLeverageRatio
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants aggregate fixed charge coverage ratio. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsAggregateFixedChargeCoverageRatio
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants aggregate fixed charge leverage ratio. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsAggregateFixedChargeLeverageRatio
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants tangible net worth component aggregate net income percent. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsTangibleNetWorthComponentAggregateNetIncomePercent
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants tangible net worth component fixed amount. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsTangibleNetWorthComponentFixedAmount
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line of credit facility covenants tangible net worth component proceeds from issuance of common stock percentage. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsTangibleNetWorthComponentProceedsFromIssuanceOfCommonStockPercentage
Namespace Prefix: | mgrc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility covenants tangible net worth description. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityCovenantsTangibleNetWorthDescription
Namespace Prefix: | mgrc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line of credit facility enhanced borrowing capacity. + References No definition available. + Details
Name: | mgrc_LineOfCreditFacilityEnhancedBorrowingCapacity
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Notes payable amount after reclassification of prepaid debt financing cost. + References No definition available. + Details
Name: | mgrc_NotesPayableAmountAfterReclassificationOfPrepaidDebtFinancingCost
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Stated criteria value for determining available facility amount. + References No definition available. + Details
Name: | mgrc_StatedCriteriaValueForDeterminingAvailableFacilityAmount
Namespace Prefix: | mgrc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Identification of the lender and information about a contractual promise to repay a short-term or long-term obligation, which includes borrowings under lines of credit, notes payable, commercial paper, bonds payable, debentures, and other contractual obligations for payment. This may include rationale for entering into the arrangement, significant terms of the arrangement, which may include amount, repayment terms, priority, collateral required, debt covenants, borrowing capacity, call features, participation rights, conversion provisions, sinking-fund requirements, voting rights, basis for conversion if convertible and remarketing provisions. The description may be provided for individual debt instruments, rational groupings of debt instruments, or by debt in total. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644 Reference 2: 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(19)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 5: 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(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_DebtInstrumentDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentDescriptionOfVariableRateBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of the frequency of periodic payments (monthly, quarterly, annual). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentFrequencyOfPeriodicPayment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + 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 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399 + Details
Name: | us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + 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 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + 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 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment. + 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 210.5-02.22(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 + Details
Name: | us-gaap_DebtInstrumentPaymentTerms
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of commitment fees for the unused borrowing capacity under the long-term financing arrangement that is available to the entity. + 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 210.5-02.22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentUnusedBorrowingCapacityFee
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + 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(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date the credit facility terminates, in CCYY-MM-DD format. + 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 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + 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 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow associated with the sale of a borrowing supported by a written promise to pay an obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfNotesReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mgrc_TwoThousandSixteenAmendmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mgrc_SeriesASeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mgrc_FourPointZeroThreePercentDueTwoThousandEighteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mgrc_SeriesBSeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mgrc_ThreePointSixEightPercentDueTwoThousandTwentyOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mgrc_SeriesCSeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mgrc_ThreePointEightFourPercentDueTwoThousandTwentyTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=mgrc_UnsecuredRevolvingCreditFacilityAfterRenewedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_UnusedLinesOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=mgrc_SweepServiceFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=mgrc_UnsecuredRevolvingCreditFacilityBeforeRenewalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=mgrc_SwingLineLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |