Earnings Per Share - Reconciliation of Number of Common Stock used in Computing Basic and Diluted Earning Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Weighted Average Number Of Shares Outstanding [Abstract]
Weighted average shares outstanding - basic	115,411,032	117,188,398	115,905,834	117,946,805
Dilutive effect of share-based awards	750,523	745,042	749,670	750,031
Weighted average shares outstanding - diluted	116,161,555	117,933,440	116,655,504	118,696,836