Performance Incentive Plan (Other Grants) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Other share grants under the 2017 Plan:
Restricted shares granted (in shares)	30,257
Restricted shares granted, weighted average share price (in dollars per share) | $ / shares	$ 40.28
Shares available under the 2017 Plan for grant, end of period (in shares)	467,259
Directors’ fees
Other share grants under the 2017 Plan:
Restricted shares granted (in shares)	13,786
Restricted shares granted, weighted average share price (in dollars per share) | $ / shares	$ 45.21
Deferred directors’ fees
Other share grants under the 2017 Plan:
Restricted shares granted (in shares)	16,471
Restricted shares granted, weighted average share price (in dollars per share) | $ / shares	$ 45.27