Consolidated Statements of Stockholders' Equity (Parenthetical) (Common Stock [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock dividend (in hundredths)	3.00%	2.00%	1.00%