Basis of Presentation - Effect of Retrospective Application of Change in Accounting Principle on Company's Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Oct. 31, 2015	Jan. 31, 2015
Current assets:
Prepaid expenses and other current assets	$ 9,485	$ 8,913
Total current assets	154,479	132,338
Noncurrent assets:
Other assets	4,050	3,907
Total assets	288,120	259,881
Current liabilities:
Current portion of long-term debt	7,332	7,335
Borrowings under credit facility	55,866	18,817
Total current liabilities	127,428	89,568
Long-term liabilities:
Long-term debt, net of current portion	20,652	26,171
Total long-term liabilities	72,443	77,923
Total liabilities and stockholders' equity	$ 288,120	259,881
As Reported
Current assets:
Prepaid expenses and other current assets		9,190
Total current assets		132,615
Noncurrent assets:
Other assets		4,849
Total assets		261,100
Current liabilities:
Current portion of long-term debt		7,489
Borrowings under credit facility		19,402
Total current liabilities		90,307
Long-term liabilities:
Long-term debt, net of current portion		26,651
Total long-term liabilities		78,403
Total liabilities and stockholders' equity		261,100
Effect of Change in Accounting Principle
Current assets:
Prepaid expenses and other current assets		(277)
Total current assets		(277)
Noncurrent assets:
Other assets		(942)
Total assets		(1,219)
Current liabilities:
Current portion of long-term debt		(154)
Borrowings under credit facility		(585)
Total current liabilities		(739)
Long-term liabilities:
Long-term debt, net of current portion		(480)
Total long-term liabilities		(480)
Total liabilities and stockholders' equity		$ (1,219)