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

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Share-based Compensation - Options Information and Valuation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized amount, options	$ 0.9		$ 0.9
Number of stock options exercisable	120,644		120,644
Weighted average exercise price of stock options that are exercisable	$ 13.03		$ 13.03
Remaining contractual life of exercisable stock options			8 years 3 months 18 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years
Expiration period			10 years
Share-based compensation recognized cost	$ 0.1	$ 0.2	$ 0.1	$ 0.3
Unrecognized cost, period for recognition			2 years 4 months 24 days