Income Taxes - Income Tax Benefits in Shareholders' Equity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Tax Benefit from Stock Compensation	$ (92,234)	$ (101,466)	$ (77,478)