Earnings per Share Purchase of Common Stock (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2015
Stock Repurchased and Retired During Period, Value	$ 19,090,000	$ 39,420,000	$ 36,740,000
10b5-1 share repurchase program [Member]
Stock Repurchase Program, Authorized Amount	$ 250,000,000			$ 50,000,000
Stock Repurchased and Retired During Period, Shares	596,084	1,582,049	1,230,050
Stock Repurchased and Retired During Period, Value	$ 19,100,000	$ 39,400,000	$ 36,700,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 142,600,000

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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