Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Summary Of Significant Accounting Policies [Line Items]
Management agreement, initial term			20 years
Number of major customers	2	3	2	3
Customer A | Two Major Customers
Summary Of Significant Accounting Policies [Line Items]
Percentage Of Accounts Receivable From Customers	16.20%		16.20%
Revenue Of Major Customers Percentage Of Total Revenue	15.40%		16.30%
Customer A | Three Major Customers
Summary Of Significant Accounting Policies [Line Items]
Revenue Of Major Customers Percentage Of Total Revenue		20.80%		24.00%
Customer B | Two Major Customers
Summary Of Significant Accounting Policies [Line Items]
Percentage Of Accounts Receivable From Customers	9.70%		9.70%
Revenue Of Major Customers Percentage Of Total Revenue	15.00%		15.50%
Customer B | Three Major Customers
Summary Of Significant Accounting Policies [Line Items]
Revenue Of Major Customers Percentage Of Total Revenue		6.30%		7.70%
Customer C | Three Major Customers
Summary Of Significant Accounting Policies [Line Items]
Revenue Of Major Customers Percentage Of Total Revenue		4.20%		4.90%