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

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Number of shares authorized for issuance under share-based payment arrangement.

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Share-based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	May 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years			5 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense	$ 3,500,000	$ 4,800,000	$ 7,200,000	$ 8,200,000
Employee service share-based compensation, unrecognized compensation costs on non-vested awards	31,600,000		$ 31,600,000
Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years			1 year
Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years			4 years
Stock-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense	0	400,000	$ 400,000	1,500,000
Employee service share-based compensation, unrecognized compensation costs on non-vested awards	0		0
Cash Settled S A Rs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, compensation expense	400,000	$ 300,000	600,000	$ 800,000
Employee service share-based compensation, unrecognized compensation costs on non-vested awards	$ 0		$ 0
2019 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)					1,885,000