XML 84 R67.htm IDEA: XBRL DOCUMENT v3.20.4
Operations and Summary of Significant Accounting Policies - Net Income Per Common Share Narrative (Details) - shares
shares in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Stock Appreciation Rights (SARs)      
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]      
Antidilutive securities excluded from computation of earnings per share (in shares) 0.3 0.2 0.5