Significant Accounting Policies (Earnings Per Share) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Dec. 16, 2014	Mar. 08, 2012	May. 02, 2011
Significant Accounting Policies [Line Items]
Common stock equivalents (in shares)	1,117,000		1,128,000	1,122,000
Anti-dilutive securities excluded from computation of diluted earnings per share (in shares)	27,000	1,278,000	28,000	779,000
Stock repurchase program authorized amount						$ 257.8	$ 323.7	$ 300.0
Stock repurchase program remaining authorized repurchase amount	$ 306.2		$ 306.2		$ 400.0	$ 400.0