Employee Benefit Plans - Defined Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans
Projected benefit obligation
Beginning of year	$ 186,400,000	$ 178,900,000
Service cost	3,000,000.0	3,000,000.0	$ 2,800,000
Interest cost	2,800,000	4,500,000	6,100,000
Actuarial (gains) loss	(7,900,000)	14,500,000
Benefits paid	(14,300,000)	(14,500,000)
End of year	170,000,000.0	186,400,000	178,900,000
Fair value of plan assets
Beginning of year	162,400,000	156,500,000
Actual (loss) return on plan assets	(400,000)	18,900,000
Benefits paid	(14,300,000)	(14,500,000)
End of year	149,200,000	162,400,000	$ 156,500,000
(Unfunded) funded status end of year	(20,800,000)	(24,000,000.0)
Accumulated benefit obligation at end of year	169,700,000	185,200,000
Amounts included in accumulated other comprehensive loss
Unrecognized actuarial losses (gross)	46,700,000	52,400,000
Unrecognized actuarial losses (net of tax)	37,500,000	42,300,000
Unrecognized prior service costs (gross)	400,000	500,000
Unrecognized prior service costs (net of tax)	300,000	400,000
Executive supplemental and director defined benefit pension plans
Projected benefit obligation
Beginning of year	23,400,000
End of year	21,300,000	23,400,000
Fair value of plan assets
Beginning of year	0
Company contributions	1,500,000	1,500,000
End of year	0	0
Accumulated benefit obligation at end of year	$ 21,100,000	$ 22,200,000