Employee Benefits - Benefit Plans and Related Amounts Recorded in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Projected benefit obligation	$ 62,297	$ 52,503	$ 44,890	$ 45,450
Pension plan assets at fair value	(28,636)	(23,444)	(19,460)	$ (18,475)
Funded status – shortfall	33,661	29,059	25,430
Accumulated benefit obligation	58,963	49,485	42,611
Amounts recorded in the Consolidated Balance Sheets for the plans
Other liabilities — accrued pension obligation	33,661	29,059	25,430
Stockholders’ equity — deferred actuarial loss	$ (9,309)	$ (8,584)	$ (5,738)
Future long-term rate of return on plan assets	1.19%
Weighted average amortization period	14 years