Pension and Other Post Retirement Benefit Plans - Schedule of Changes in Benefit Obligation, and Plan Assets, Funded Status of the Plan, Assets and Liabilities Recognized in the Balance Sheets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in Benefit Obligation:
Benefit obligation at beginning of year	$ 73,193	$ 82,157
Service cost	39	8	$ 10
Interest cost	2,975	2,816	3,353
Actuarial (gain) loss	4,007	(6,129)
Benefits paid	(5,145)	(5,659)
Net transfer in from MBT acquisition	(1,701)	0
Benefit obligation at end of year	76,770	73,193	82,157
Change in Plan Assets:
Fair value of plan assets at beginning of year	76,736	85,213
Actual return on plan assets	12,972	(3,427)
Employer contributions	558	609
Benefits paid	(5,145)	(5,659)
End of year	85,121	76,736	$ 85,213
Funded status at end of year	8,351	3,543
Assets and Liabilities Recognized in the Balance Sheets:
Deferred tax asset	3,278	3,855
Assets	13,291	7,024
Liabilities	4,940	3,481
Amounts Recognized in Accumulated Other Comprehensive Income Not Yet Recognized as Components of Net Periodic Cost, net of tax, consist of:
Accumulated loss	(9,712)	(14,111)
Prior service cost	(325)	(409)
Total	$ (10,037)	$ (14,520)