Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense	$ 4,741,000	$ 3,615,000	$ 5,588,000	$ 3,474,000
Effective tax rate for continuing operations	21.40%	28.30%	20.70%	16.80%
Income tax benefit from foreign operations	$ 0	$ 0	$ 0
Corporate income tax rate	21.00%	21.00%	21.00%	21.00%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current and deferred foreign income tax expense (benefit) attributable to income (loss) from continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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