Stockholders' Equity (Dividends) (Details) (USD $)	3 Months Ended												12 Months Ended			0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	May 01, 2014 Dividend Declared [Member]
Dividends [Line Items]
Cash dividends paid	$ 0.48	$ 0.48	$ 0.48	$ 0.48	$ 0.40	$ 0.40	$ 0.40	$ 0.40	$ 0.32	$ 0.32	$ 0.32	$ 0.29	$ 1.92	$ 1.60	$ 1.25
Dividends payable, declaration date																May 01, 2014
Cash dividend declared																$ 0.55
Dividends payable date																Jun. 30, 2014
Dividends payable, date of record																Jun. 13, 2014