Stock Compensation Plans - Stock-Based Compensation Expense and Related Tax Benefits (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 9,045	$ 8,165	$ 30,524	$ 29,256
Less: Tax benefit	(1,803)	(1,143)	(5,765)	(4,666)
Total stock-based compensation expense, after tax	7,242	7,022	24,759	24,590
Equity-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	8,195	8,126	27,177	26,426
Liability-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 850	$ 39	$ 3,347	$ 2,830

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

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