Commitments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Line Items]
Committed purchase obligations	$ 96,380
Contribution by employer for employee saving plan	19,624	$ 19,600	$ 18,210
Standby Letters of Credit
Commitments And Contingencies Disclosure [Line Items]
Contingently liable for letters of credit, amount	$ 69,489