Stock-Based Compensation and Stock Awards - Restricted Stock Awards - Additional Information (Detail) - Restricted stock awards - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Restricted stock awards compensation expense	$ 8.6	$ 8.8	$ 8.4
Income tax benefit recognized	2.0	$ 1.5	$ 1.9
Unrecognized compensation expense related to share based compensation	$ 7.4
Period of recognition for unrecognized compensation expense related to nonvested stock options (in years)	2 years 10 months 24 days
Antidilutive securities (in shares)	45,857	240,000	186,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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