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Stock Compensation Plans and Other Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended			84 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022	May 31, 2022	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved for issuance (in shares)					1,200,000
Shares available for future grants (in shares)	1,600,000			1,600,000
Number of stock options granted (in shares)				0
Stock-based compensation expense	$ 31,700,000	$ 16,200,000	$ (4,900,000)
Tax benefit (expense) from stock-based compensation arrangements	7,000,000	3,700,000	(914,000,000)
Aggregate intrinsic value of options exercised	6,700,000	11,700,000	4,100,000
Actual tax benefit realized from option exercises	1,800,000	3,100,000	1,100,000
Cash received from option exercises	5,200,000	14,000,000	9,700,000
Excess (deficit) tax benefit over estimate	(580,000)	(40,000)	848,000
Unrecognized compensation cost	$ 37,800,000			$ 37,800,000
Unrecognized compensation cost, period for recognition	2 years
Fair value of shares vested	$ 4,500,000	1,500,000	14,700,000
Expense for employer contribution to plan	16,200,000	15,600,000	13,800,000
Cash Incentive and Retention Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense related to plan	0	0	0
Cash awards paid	0	$ 0	$ 0
Cash awards outstanding	$ 0			$ 0
Directors Deferred Fee and Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares authorized (in shares)			200,000
Issued to directors (in shares)	59,174	23,909	19,928
Obligation to issue (in shares)	313,409			313,409
Available for future issuance under DDFS Plan (in shares)	121,119			121,119
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term	10 years
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding (in shares)	610,155	476,813	234,794	610,155		144,328
Restricted Shares \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Restricted Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
LTIP Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Term	7 years
LTIP Awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance based award payouts	0.00%
LTIP Awards \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance based award payouts	150.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Performance period	3 years
Shares outstanding (in shares)	545,379	557,255	482,608	545,379		465,515
Performance Shares \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares outstanding (in shares)	800,000			800,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of purchase price of shares	95.00%
Employee stock purchase plan issuance (in shares)	40,421	44,021	75,763
Compensation expense employee stock purchase plan	$ 0	$ 0	$ 0
Increase in shares authorized (in shares)		200,000
Common stock obligation to issue (in shares)	8,638			8,638
Available for future grants under ESPP (in shares)	212,472			212,472