Retirement Plans - Schedule of Changes in Benefit Obligations and Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0
Interest cost	34	38	49
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Funded Status at End of Year	834	883
Unrecognized transition obligation	0	0
Unrecognized net gain	463	584
Amounts recognized in retained earnings	1,297	1,467
Change in Benefit Obligation [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	883	1,188
Service cost	0	0
Interest cost	34	38
Amendments	0	0
Actuarial gain	61	(174)
Net benefits paid	(144)	(169)
Benefit obligation at end of year	834	883	1,188
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net benefits paid	(144)	(169)
Change In Plan Assets [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Net benefits paid	(144)	(169)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	144	169
Net benefits paid	(144)	(169)
Fair value of plan assets at end of year	$ 0	$ 0	$ 0