Incentive Plans - Summary of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Prepaid Compensation Asset	$ 74,597	$ 76,362
Compensation Liability	236,273	188,962
LFI and Other Similar Deferred Compensation Arrangements [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Prepaid Compensation Asset	74,597	76,362
Prepaid Compensation Asset, Granted	101,529
Prepaid Compensation Asset, Forfeited	(1,702)
Prepaid Compensation Asset, Amortization	(101,663)
Prepaid Compensation Asset, Other	71
Compensation Liability	226,026	$ 188,022
Compensation Liability, Granted	101,529
Compensation Liability, Settled	(96,976)
Compensation Liability, Forfeited	(3,455)
Compensation Liability, Amortization	31,657
Compensation Liability, Adjustment for estimated forfeitures	5,340
Compensation Liability, Other	$ (91)