Debt - Additional Information (Detail) - USD ($)		3 Months Ended
	Mar. 22, 2019	Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Obligations under finance leases		$ 75,533,000	$ 74,399,000
LIBOR Loans
Debt Instrument [Line Items]
Revolving credit facility, margin rate		1.50%
Base Rate Loans
Debt Instrument [Line Items]
Revolving credit facility, margin rate		0.50%
Senior Notes 5.875 Percent Due 2024
Debt Instrument [Line Items]
Senior notes, face amount		$ 250,000,000.0
Senior notes, interest rate		5.875%
Senior notes, maturity date		Jul. 01, 2024
Senior notes, interest payment term		Interest on the 2024 Notes is payable semiannually in arrears on January 1 and July 1.
Second Amended and Restated $1 billion ABL Credit Agreement
Debt Instrument [Line Items]
Credit Agreement, initiation date	Mar. 22, 2019
Unused line fee percentage in respect of unutilized commitments		0.225%
Credit Agreement, interest rate terms		Loans made under the (i) U.S. Subfacility bear interest at a rate equal to, at Mobile Mini’s option, either (a) the London interbank offered rate (“LIBOR”) plus an applicable margin (“LIBOR Loans”) or (b) the prime rate plus an applicable margin (“Base Rate Loans”);  (ii) U.K. Subfacility denominated in British Pounds bear interest at LIBOR plus an applicable margin and loans denominated in Euros bear interest at the Euro interbank offered rate plus an applicable margin; and (iii) Canadian Subfacility bear interest at a rate equal to, at Mobile Mini’s option, either (a) the Canadian prime rate plus an applicable margin  or (b) the Canadian Dollar bankers’ acceptance rate  plus an applicable margin.  As of March 31, 2020, the applicable margins are 1.50% for LIBOR Loans and 0.50% for Base Rate Loans.  Mobile Mini is also required to pay an unused line fee in respect of the unutilized commitments under the Credit Agreement at a fee rate of 0.225% per annum, as well as customary letter of credit fees
Minimum fixed charges coverage ratio		100.00%
Line of credit, specified excess borrowing availability for financial maintenance covenants to be applicable		$ 90,000,000
Applicable percentage of revolving loan commitment and aggregate borrowing base		10.00%
Line of credit, covenant		Credit Agreement are subject to customary conditions, including sufficient availability under the respective borrowing base.  The Credit Agreement also contains various financial and nonfinancial covenants which require Mobile Mini to, among other things, comply with a minimum fixed charge coverage ratio of 1.00 to 1.00 as of the last day of each quarter, upon specified excess availability under the Credit Agreement falling below the greater of (y) $90 million and (z) 10% of the lesser of the then total revolving loan commitment and aggregate borrowing base.
Second Amended and Restated $1 billion ABL Credit Agreement | First Lien Senior Secured Revolving Credit Facility
Debt Instrument [Line Items]
Credit Agreement, borrowing capacity	$ 1,000,000,000
Credit Agreement, maturity date		Mar. 22, 2024
Second Amended and Restated $1 billion ABL Credit Agreement | First Lien Senior Secured Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Credit Agreement, increase in additional commitments	500,000,000
Second Amended and Restated $1 billion ABL Credit Agreement | U.S. Lenders | Standby Letters of Credit
Debt Instrument [Line Items]
Credit Agreement, borrowing capacity	50,000,000
Second Amended and Restated $1 billion ABL Credit Agreement | U.K. Based Lenders | Standby Letters of Credit
Debt Instrument [Line Items]
Credit Agreement, borrowing capacity	20,000,000
Second Amended and Restated $1 billion ABL Credit Agreement | Canadian Based Lenders | Standby Letters of Credit
Debt Instrument [Line Items]
Credit Agreement, borrowing capacity	$ 20,000,000