Acquisitions (Summary Of Estimate Of Fair Value Of Identifiable Assets Acquired And Liabilities Assumed) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jan. 31, 2016	Jul. 31, 2015	Oct. 31, 2014	Apr. 30, 2016	Apr. 30, 2015	Jan. 19, 2016	Jun. 30, 2015	Sep. 11, 2014
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				$ 20,245	$ 182,500
Wilmot [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment						$ 12,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill						400
Goodwill, Acquired During Period	$ 7,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable						$ 300
Business Combination, Consideration Transferred	$ 20,200
Perisher [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables							$ 1,494
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment							126,287
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill							5,458
Goodwill, Acquired During Period		$ 31,657
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets							170,280
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable							11,394
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue							15,906
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities							$ 45,729
Business Combination, Consideration Transferred		$ 124,551
PCMR [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables								$ 930
Business Acquisition, Purchase Price Allocation, Current Assets, Other Current Assets								3,075
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment								76,605
Business Acquisition, Purchase Price Allocation, Deferred Taxes Asset (Liab), Net, Noncurrent								7,428
Business Acquisition, Purchase Price Allocation, Real estate held for sale and investment								7,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								27,650
Goodwill, Acquired During Period			$ 92,516
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets								215,204
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable								1,935
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue								4,319
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities								$ 6,254
Business Combination, Consideration Transferred			$ 208,950