Acquisitions (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Business Combinations [Abstract]
Revenues	$ 323,890	$ 349,473	$ 664,089	$ 712,673
Net income (loss)	$ 904	$ (1,011)	$ (518)	$ (3,217)