Share-Based Compensation Plans (Allocated Share-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Abstract]
Grants of common shares and options	$ 13,330	$ 12,736	$ 12,371
Capitalized share-based compensation	(1,054)	(1,017)	(1,385)
Share-based compensation expense	$ 12,276	$ 11,719	$ 10,986

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost capitalized for award under share-based payment arrangement.

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Amount of noncash expense for share-based payment arrangement.

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