Earnings Per Share - Weighted-Average Shares Outstanding for Computation of Basic and Diluted Income per Common Share (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Basic method	153,507,109	163,992,427	172,974,491
Dilutive stock options	0	820,001	1,234,274
Diluted method	153,507,109	164,812,428	174,208,765
Unvested stock awards	$ 0

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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

+ References

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-Publisher FASB
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-Topic 718
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- Definition

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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