Changes in Stockholders' Equity and Temporary Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended
	Jul. 31, 2012	Sep. 30, 2012	Sep. 30, 2012
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount	$ 50.0
Stock repurchased and retired during period, shares		224,007
Stock repurchased and retired during period		$ 9.5	$ 9.5
Stock repurchased and retired during period, average cost, in dollars per share		$ 42.44