Stockholders' Equity - Adjustments for Items Reclassified Out of AOCI (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications, net of tax	$ 4,717	$ 10,735	$ 7,951
Employee Benefit Plans [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization relating to employee benefit plans	5,884	13,070	10,171
Less - related income taxes	1,167	2,335	2,220
Total reclassifications, net of tax	$ 4,717	$ 10,735	$ 7,951