Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note [Abstract]

Stockholders' Equity

Stockholders' Equity

Common and Treasury Stock

The following table summarizes the changes in shares of Common Stock outstanding and Treasury Stock:

	Common Stock Outstanding	Treasury Stock
Balance at December 31, 2017	186,603,738	136,734,174
Issuance of common stock	1,043,809	(1,043,809)
Conversions to common stock	27,535	(27,535)
Balance at December 31, 2018	187,675,082	135,662,830
Repurchases of common stock	(18,595,315)	18,595,315
Issuance of common stock	1,276,797	(1,276,797)
Conversions to common stock	92,379	(92,379)
Balance at December 31, 2019	170,448,943	152,888,969
Issuance of common stock	1,526,245	(1,526,245)
Balance at December 31, 2020	171,975,188	151,362,724

At December 31, 2020, 41,956,401 shares were reserved for issuance under our stock plans and dividend reinvestment program.