Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Detail) - USD ($) $ in Thousands	8 Months Ended	12 Months Ended
Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 1,000		$ 1,600	$ 1,000
Unrecognized Tax Benefits, Beginning Balance	$ 84,213	$ 84,213	80,783	79,179
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions		0	3,927	1,604
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions		8,412	0	0
Unrecognized Tax Benefits, Ending Balance		85,758	84,213	80,783
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions		$ (6,867)	$ (497)	$ 0

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Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 10B
-URI http://asc.fasb.org/extlink&oid=116821951&loc=SL37586934-109318

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-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
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- Definition

Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 15
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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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