Earnings per Share - Reconciliation of Weighted-Average Common Shares Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Determination of shares:
Weighted-average common shares outstanding (in shares)	115,700,000	97,100,000	90,900,000
Diluted weighted-average common shares outstanding (in shares)	117,800,000	100,300,000	93,400,000
Anti-dilutive securities, stock options (in shares)	2,353,307	656,588	51,803
Stock options
Determination of shares:
Assumed conversion of dilutive employee stock-based awards and restricted stock (in shares)	1,800,000	3,000,000.0	2,400,000
Restricted stock
Determination of shares:
Assumed conversion of dilutive employee stock-based awards and restricted stock (in shares)	300,000	200,000	100,000