Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Summary of Weighted Average Asset Allocation of Plan Assets by Asset Category (Detail)

v3.19.1
Employee Benefit Plans - Summary of Weighted Average Asset Allocation of Plan Assets by Asset Category (Detail)
Mar. 31, 2019
Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]    
Weighted average asset allocation 100.00% 100.00%
Equity Securities [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Target Plan Asset Allocations 50.00% 65.00%
Weighted average asset allocation 49.00% 67.00%
Debt Securities [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Target Plan Asset Allocations 50.00% 35.00%
Weighted average asset allocation 51.00% 33.00%