Stockholders' Equity Dividends (Details) - $ / shares	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015
Class of Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.3400	$ 0.3150
July 2016 dividend payment [Member]
Class of Stock [Line Items]
Dividends Payable, Date Declared, Month and Year	May 26, 2016
Dividends Payable, Date of Record	Jun. 06, 2016
Dividends Payable, Date to be Paid	Jul. 01, 2016
Common Stock, Dividends, Per Share, Declared	$ 0.17
October 2016 dividend payment [Member]
Class of Stock [Line Items]
Dividends Payable, Date Declared, Month and Year	Jul. 28, 2016
Dividends Payable, Date of Record	Sep. 01, 2016
Dividends Payable, Date to be Paid	Oct. 03, 2016
Common Stock, Dividends, Per Share, Declared	$ 0.17