Stock-Based Compensation - Schedule of Information Related to Outstanding SOSARS (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised	(10,000)	(101,000)	(41,000)
Stock Only Stock Appreciation Rights (SOSARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Outstanding	1,291,947	2,334,742	2,561,846
Exercised	(58,460)	(596,360)	(158,545)
Canceled / forfeited	(151,074)	(446,435)	(68,559)
Ending Balance, Outstanding	1,082,413	1,291,947	2,334,742
Exercisable at December 31,	1,082,413	1,291,947	2,134,297
Vested and expected to vest	1,082,413	1,291,947	2,334,742
Beginning Balance, Weighted Average Exercise Price, Outstanding	$ 20.05	$ 18.08	$ 17.87
Weighted Average Exercise Price, Exercised	12.85	15.56	13.31
Weighted Average Exercise Price, Canceled / forfeited	20.25	21.06	21.09
Ending Balance, Weighted Average Exercise Price, Outstanding	20.40	20.05	18.08
Weighted Average Exercise Price, Exercisable at December 31,	$ 20.40	$ 20.05	$ 18.13
Compensation expense		$ 40	$ 317

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

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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