Discontinued Operations - Carrying Amount of Assets Held for Sale in Consolidated Balance Sheet (Details) - USD ($)	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Discontinued Operations and Disposal Groups [Abstract]
Total assets of discontinued operations			$ 42,937,000
Loss on disposal of discontinued operations, net of tax	$ 0	$ (1,537,000)	(9,192,000)
Assets held for sale	$ 0		$ 33,745,000