Stockholders' Equity (Narratives) (Details) - $ / shares	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Dividends declared one [Member]
Dividends Declared
Dividends payable, date declared	Mar. 15, 2016
Dividend paid, amount per share	$ 1.00
Dividends payable, date of record	Apr. 05, 2016
Dividends payable, date to be paid	Apr. 21, 2016
Dividends declared two [Member]
Dividends Declared
Dividends payable, date declared	Aug. 28, 2015
Dividend paid, amount per share	$ 3.00
Dividends payable, date of record	Sep. 16, 2015
Dividends payable, date to be paid	Oct. 02, 2015
Dividends declared three [Member]
Dividends Declared
Dividends payable, date declared	Jun. 04, 2015
Dividend paid, amount per share	$ 1.00
Dividends payable, date of record	Jun. 19, 2015
Dividends payable, date to be paid	Jul. 01, 2015
Dividends declared four [Member]
Dividends Declared
Dividends payable, date declared		Feb. 04, 2015
Dividend paid, amount per share		$ 1.00
Dividends payable, date of record		Mar. 06, 2015
Dividends payable, date to be paid		Mar. 17, 2015
Dividends declared five [Member]
Dividends Declared
Dividends payable, date declared			Dec. 04, 2013
Dividend paid, amount per share			$ 1.00
Dividends payable, date of record			Jan. 10, 2014
Dividends payable, date to be paid			Feb. 14, 2014