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Equity Compensation Plans - Restricted Stock (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-Average Grant Date Fair Value, Awards granted	$ 48.82	$ 40.86	$ 41.69
Market value of restricted stock shares vesting	$ 21.0	$ 32.8	$ 17.0
Restricted stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted common stock shares granted to certain members of executive management	692
Weighted-Average Grant Date Fair Value, Awards granted	$ 48.82
Market-based Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Restricted common stock shares granted to certain members of executive management		100
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
Minimum \| Restricted stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
Maximum \| Restricted stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	4 years