Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Operating Loss Carryforwards [Line Items]
Statutory federal tax rate									35.00%	35.00%	35.00%
Effective tax rate, change from prior year, percent									0.40%
Effective Income Tax Rate Reconciliation, Tax Contingency, Percent									4.30%	2.80%	(1.00%)
Effective tax rate, impact of discrete tax items										1.50%
Significant state apportionment changes									0.00%	(4.30%)	0.00%
Net loss from discontinued operations, net of tax benefits	$ (3,218)	$ (3,302)	$ (2,805)	$ (2,647)	$ (563)	$ (3,080)	$ (2,489)	$ (3,154)	$ (11,972)	$ (9,286)	$ (13,081)
Tax benefits from discontinued operations									6,986	5,414	8,125
Valuation on deferred tax assets increase									1,300
Valuation allowance	22,844				21,515				$ 22,844	21,515
Document Fiscal Year Focus									2017
Unrecognized tax benefits that would impact effective tax rate	118,200				82,300				$ 118,200	82,300	55,300
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	14,000								14,000
Total gross interest and penalties accrued	21,000				$ 22,300				21,000	22,300	24,700
Settlement reducing uncertain tax benefits									293	$ 450	$ 10,450
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries	10,000								10,000
State And Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 22,700								$ 22,700