Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock authorized (in shares)	5,000,000	5,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 5.00	$ 5.00
Common stock authorized (in shares)	150,000,000	150,000,000
Common stock issued (in shares)	59,296,725	59,296,725
Common stock outstanding (in shares)	56,200,487	56,855,002
Treasury stock (in shares)	3,096,238	2,411,723