Stockholders' Equity (Narrative) (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Jul. 31, 2016	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2018	Aug. 06, 2020	Feb. 29, 2012
Class of Stock [Line Items]
Number of shares purchased from plan participants (in shares)			4,424
Integrated Global Concepts, Inc
Class of Stock [Line Items]
Shares acquired and subsequently retired (in shares)		935,231
2012 Repurchase Program
Class of Stock [Line Items]
Maximum number of shares authorized to be repurchased (in shares)							5,000,000
Shares repurchased under the program (in shares)	4,100,000			1,140,819	600,000
Aggregate cost of shares repurchased	$ 204.6			$ 87.5	$ 42.5
Number of remaining shares available for purchase (in shares)		0
2020 Repurchase Program
Class of Stock [Line Items]
Maximum number of shares authorized to be repurchased (in shares)						10,000,000
Shares repurchased under the program (in shares)	2,000,000			2,000,000
Aggregate cost of shares repurchased	$ 141.8			$ 141.8