Statements of Consolidated Shareholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax provision (benefit) for recognized net actuarial loss (gain)	$ 145	$ 112
Tax provision (benefit)	$ 229	$ (433)
Common Shares [Member]
Issuance of common shares	78,730	88,377	88,377
Common Shares Issued to Rabbi Trust [Member]
Common shares distributed from rabbi trust	22,370	19,396	1,989
Deferred Compensation Liability [Member]
Common shares distributed from rabbi trust	22,370	19,396	1,989
Paid In Capital [Member]
Issuance of common shares	78,730	88,377	88,377
Retained Earnings [Member]
Cash dividends declared per share	$ 0.80	$ 0.80	$ 0.80
Treasury Stock [Member]
Purchase of common shares	73,460	120,848	120,848
Unrecognized Pension Benefit Cost [Member]
Tax provision (benefit) for recognized net actuarial loss (gain)	$ 145	$ 112	$ 123
Tax provision (benefit)	$ 229	$ 433	$ 60