Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Income Taxes [Abstract]
Minimum taxable income in the future to fully utilize gross deferred tax assets	$ 71,300,000
Hypothetical tax benefits related to stock-based awards	24,118,000
Total unrecognized tax benefits, excluding interests - Ending and beginning balances	6,763,000	7,056,000	6,613,000
Unrecognized tax benefits that would positively impact Comtech's effective tax rate, if recognized	5,719,000	6,060,000
Income taxes payable non-current	3,811,000	5,220,000
Decrease in unrecognized tax benefits due to the expiration of the statute of limitations or settlements with tax authorities for previously filed returns, minimum	3,000,000
Decrease in unrecognized tax benefits due to the expiration of the statute of limitations or settlements with tax authorities for previously filed returns, maximum	4,000,000
Expected recognition of net discrete tax benefit, Subsequent event	3,300,000
Interest accrued relating to income taxes, net of the related income tax benefit	$ 545,000	$ 580,000