Income Taxes - Additional Information (Detail)	3 Months Ended
	Apr. 30, 2015	Apr. 30, 2014
Income Tax Examination [Line Items]
Effective Income Tax Rate Reconciliation, Percent	34.70%	35.10%
Tax Legislation Impact		2.0
Valuation Allowance Change Impact		1.3
Minimum [Member]
Income Tax Examination [Line Items]
Income tax examination, tax years	2006
Minimum [Member] | Internal Revenue Service [Member]
Income Tax Examination [Line Items]
Income tax examination, tax years	2010
Minimum [Member] | New York City [Member]
Income Tax Examination [Line Items]
Income tax examination, tax years	2011
Maximum [Member] | Internal Revenue Service [Member]
Income Tax Examination [Line Items]
Income tax examination, tax years	2012
Maximum [Member] | New York City [Member]
Income Tax Examination [Line Items]
Income tax examination, tax years	2012