Stockholders' Equity Dividends (Details) - $ / shares		3 Months Ended		6 Months Ended
	Nov. 17, 2016	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Class of Stock [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 0	$ 0	$ 0.34	$ 0.315
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
Subsequent Event [Member] | January 2017 dividend payment [Member]
Class of Stock [Line Items]
Dividends Payable, Date Declared, Month and Year	Nov. 17, 2016
Dividends Payable, Date of Record	Dec. 02, 2016
Dividends Payable, Date to be Paid	Jan. 03, 2017
Common Stock, Dividends, Per Share, Declared	$ 0.1825