Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Organization Consolidation And Presentation [Line Items]
Cash equivalents	$ 0		$ 4,400,000
Repurchases of common stock under share repurchase program (shares)	0.1	0.9
Weighted average cost of repurchased shares	$ 16.20	$ 17.07
Repurchases of common stock under share repurchase program	$ 1,416,000	$ 15,709,000
Share repurchase program authorized	75,000,000.0
Remaining under current repurchase authorization	54,200,000
Operating lease right-of-use assets	$ 133,700,000		$ 139,907,000

[Line Items] for Disclosures of organization, consolidation and basis of presentation of financial statements.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of lessee's right to use underlying asset under operating lease.

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Amount of stock repurchase plan authorized.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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