Derivative Instruments - Offsetting Liabilities (Detail) - USD ($) $ in Thousands	Jul. 31, 2019	Jan. 31, 2019
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	$ 518	$ 3,135
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheets	518
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Financial Instruments	(518)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Cash Collateral Pledged	0
Net Liabilities Exposed	0
Counterparty A
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	0
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheets	0
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Financial Instruments	0
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Cash Collateral Pledged	0
Net Liabilities Exposed	0
Counterparty B
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	102
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheets	102
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Financial Instruments	(102)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Cash Collateral Pledged	0
Net Liabilities Exposed	0
Counterparty C
Offsetting Liabilities [Line Items]
Gross Amounts of Recognized Liabilities	416
Gross Amounts Offset in the Condensed Consolidated Balance Sheets	0
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheets	416
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Financial Instruments	(416)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheets, Cash Collateral Pledged	0
Net Liabilities Exposed	$ 0

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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