Income Taxes - Narrative (Details) - USD ($)	3 Months Ended			12 Months Ended
	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Income Tax Disclosure [Abstract]
Blended tax rate				26.90%	35.00%	35.00%
Revaluation benefit due to TCJA			$ 8,398,000
TCJA expenses related to deemed repatriation of deferred foreign income		$ 0	294,000
TCJA, Revaluation of deferred tax assets and liabilities, provisional income tax expense (benefit)	$ 8,657,000		$ 8,692,000
TJCA, measurement period adjustment, expense reduction related to deemed repatriation of deferred foreign income		$ 294,000
Consolidated effective tax rate (as a percent)				22.50%	32.80%	36.20%
Repatriated dividends				$ 0	$ 0
Cumulative amount of undistributed earnings indefinitely reinvested in foreign subsidiaries	$ 32,774,000			$ 32,774,000