Share-Based Employee Compensation - Share-Based Compensation Related to Employees and Directors (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cost of employee share-based compensation included in income (loss), before income tax	$ 10,927,000	$ 12,896,000	$ 13,530,000
Granted, number of units	2,513,000	2,966,000	3,112,000
Payments to acquire investments	8,414,000	9,930,000	10,418,000
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cost of employee share-based compensation included in income (loss), before income tax	763,000	961,000	976,000
Operating expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cost of employee share-based compensation included in income (loss), before income tax	$ 10,164,000	$ 11,935,000	$ 12,554,000