Shares used to calculate earnings per share (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Notes to Financial Statements [Abstract]
Basic	49.4	49.1	49.3	49.0
Effect of dilutive stock options and awards	0.5	0.3	0.0	0.0
Diluted	49.9	49.4	49.3	49.0
Antidilutive stock options and awards excluded from denominator	0.3	0.5	1.5	1.9
Share-based goods and nonemployee services transaction, quantity of securities issued	0.5	0.5	0.5	0.5