Stockholders' Equity (Stock Transactions - Narrative) (Details) - $ / shares		3 Months Ended
	May 31, 2018	Mar. 31, 2018	Mar. 31, 2017	Apr. 27, 2018
Class of Stock [Line Items]
Dividends declared per common share, during the period (in dollars per share)		$ 0.30	$ 0.30
At The Market Equity Offering Program
Class of Stock [Line Items]
Issuance of common stock (shares)		0
Subsequent Event
Class of Stock [Line Items]
Dividends declared per common share, during the period (in dollars per share)	$ 0.30
Subsequent Event | At The Market Equity Offering Program
Class of Stock [Line Items]
Number of authorized shares remaining under offering program (shares)				5,868,697