Employee Benefit Plans - Net Periodic Benefit Cost and General Information (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of net periodic benefit cost
Mandatory minimum employer contributions to pension plans	$ 0	$ 0
Discretionary contributions	$ 3,600,000
Defined Contribution Plans
Maximum company match (as a percent)	4.00%
Employer contributions for the savings account	$ 19,900,000	$ 20,300,000	$ 16,900,000
Maximum percentage of employee compensation match by employer to employee stock ownership plan	50.00%
Common shares held (in shares)	0.5	0.6	0.7
Deferred Compensation - Cash
Deferred compensation plan, employer matching contribution (percent)	4.00%
Deferred compensation arrangement, compensation distribution period	10 years
Cash
Deferred Compensation - Cash
Deferred compensation, Rabbi Trust	$ 4,400,000	$ 4,000,000
Short-term Investments
Deferred Compensation - Cash
Deferred compensation, Rabbi Trust	$ 11,500,000	$ 8,100,000
Defined Benefit Plans
Weighted-average assumptions for benefit obligations
Discount rate (as a percent)	4.80%	5.00%
Rate of compensation increase (as a percent)	3.80%	3.80%
Weighted-average assumptions for net periodic benefit cost
Discount rate (as a percent)	5.10%	2.60%	2.20%
Rate of compensation increase (as a percent)	3.80%	3.80%	3.80%
Expected long-term return on plan assets (as a percent)	6.00%	6.60%	6.60%
Weighted-average cash balance interest crediting rate (as a percent)	4.00%	4.00%	4.00%
Components of net periodic benefit cost
Service cost	$ 2,100,000	$ 2,300,000	$ 3,000,000.0
Interest cost	6,300,000	3,300,000	2,800,000
Expected return on plan assets	(8,200,000)	(9,500,000)	(9,700,000)
Amortization of unrecognized net loss	1,300,000	5,000,000.0	6,200,000
Amortization of unrecognized prior service credit	100,000	0	100,000
Settlement expense	0	0	1,700,000
Net periodic benefit cost	1,600,000	1,100,000	4,100,000
Company's contribution to pension plan	5,100,000	3,500,000
Fair value of plan assets	114,800,000	114,900,000	$ 149,200,000
Estimated future benefit payments
2024	16,600,000
2025	13,600,000
2026	13,800,000
2027	13,300,000
2028	12,700,000
2029-2033	54,500,000
Executive Supplemental and Director Defined Benefit Pension Plans
Components of net periodic benefit cost
Company's contribution to pension plan	1,500,000	1,500,000
Fair value of plan assets	0	$ 0
Expected employer contributions in next fiscal year	$ 1,500,000