Income tax	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income tax	Income taxThe Company’s and the Utilities’ effective tax rates (combined federal and state income tax rates) were 20% and 21%, respectively, for the six months ended June 30, 2022. These rates differed from the combined statutory rates, due primarily to the Utilities’ amortization of excess deferred income taxes related to the provision in the 2017 Tax Cuts and Jobs Act that lowered the federal income tax rate from 35% to 21%, the tax benefits derived from the low income housing tax credit investments and the non-taxability of the bank-owned life insurance income. The Company’s and the Utilities’ effective tax rates were each 21% for the six months ended June 30, 2021. In August 2020, the Internal Revenue Service notified the Company that its 2017 and 2018 income tax returns would be examined. The Company was previously audited every year through 2011, at which time the IRS changed their internal policies regarding audit frequency. The audit is still in progress and the Company has responded to all information requests received. The Company has not been notified of any material audit adjustments to date.