Notes payable amount after reclassification of prepaid debt financing cost.

No definition available.

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Namespace Prefix:	mgrc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

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Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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Balance Type:	debit
Period Type:	instant

- Definition

Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-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

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-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

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- Details

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- Details

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Notes Payable - Components of Notes Payable (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Debt Instrument [Line Items]
Notes payable	$ 298,603				$ 303,473
Unamortized debt issuance cost	(39)				(59)
Notes payable, net	298,564	$ 309,006	$ 314,860	$ 300,595	303,414	$ 323,117	$ 330,287	$ 323,483
Unsecured Revolving Lines of Credit [Member]
Debt Instrument [Line Items]
Notes payable	198,603				183,473
Series A senior notes [Member] \| 4.03% Series A senior notes due in 2018 [Member]
Debt Instrument [Line Items]
Notes payable	0				20,000
Series B senior notes [Member] \| 3.68% Series B senior notes due in 2021 [Member]
Debt Instrument [Line Items]
Notes payable	40,000				40,000
Series C senior notes [Member] \| 3.84% Series C senior notes due in 2022 [Member]
Debt Instrument [Line Items]
Notes payable	$ 60,000				$ 60,000