Fair Value Measurements (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended								0 Months Ended		0 Months Ended	9 Months Ended					3 Months Ended	9 Months Ended
	Feb. 29, 2012 item	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013 Recurring basis Level 1	Jul. 31, 2012 Recurring basis Level 1	Apr. 30, 2013 Recurring basis Level 2	Jul. 31, 2012 Recurring basis Level 2	Apr. 30, 2013 Recurring basis Level 3	Jul. 31, 2012 Recurring basis Level 3	Feb. 11, 2011 Recurring basis Level 3 ConFirm Monitoring Business	Mar. 31, 2012 Recurring basis Level 3 ConFirm Monitoring Business	Aug. 02, 2011 Recurring basis Level 3 Byrne Medical Business	Apr. 30, 2013 Recurring basis Level 3 Byrne Medical Business	Apr. 30, 2013 Recurring basis Total	Jul. 31, 2012 Recurring basis Total	Apr. 30, 2013 Interest rate swap agreements	Jul. 31, 2012 Interest rate swap agreements	Apr. 30, 2013 Cash flow hedge Interest rate swap agreements Reclassification from accumulated other comprehensive income	Apr. 30, 2013 Cash flow hedge Interest rate swap agreements Reclassification from accumulated other comprehensive income
Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis
Number of existing senior lenders of debt, whose variable interest cash flows will be exchanged by the entity with fixed interest cash flows	1
Interest expense		$ 733,000	$ 884,000	$ 2,141,000	$ 2,861,000															$ (53,000)	$ (168,000)
Cash flow projection period of the acquiree used to estimate fair value												1 year
Discount rate of cash flow projections (as a percent)												7.00%		14.00%
Initial contingent consideration liability												656,000		2,700,000
Price floor period														3 years
Estimated contingent consideration range, low end														0
Estimated contingent consideration range, high end														10,000,000
Impact of $1.00 decrease in stock price on fair value of price floor liability															36,000
Impact of $1.00 increase in stock price on fair value of price floor liability															31,000
Assets:
Money markets						4,258,000	3,916,000									4,258,000	3,916,000
Total assets						4,258,000	3,916,000									4,258,000	3,916,000
Acquisitions payable:
Contingent consideration											1,500,000				0		1,500,000
Contingent consideration paid													855,000
Price floor										255,000	1,037,000					255,000	1,037,000
Initial price floor														3,000,000
Contingent consideration period														2 years
Portion of the contingent consideration period that has lapsed															21 months
Total acquisitions payable										255,000	2,537,000					255,000	2,537,000
Other liabilities:
Interest rate swap agreements								240,000	335,000							240,000	335,000
Total other liabilities								240,000	335,000							240,000	335,000
Total liabilities								240,000	335,000	255,000	2,537,000					495,000	2,872,000
Additional disclosures
Current portions of derivative liabilities																		174,000	212,000
Long-term portions of derivative liabilities																		$ 66,000	$ 123,000