Employee Benefits - Benefit Plans and Related Amounts Recorded in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Projected benefit obligation	$ 44,890	$ 45,450	$ 38,400	$ 35,870
Pension plan assets at fair value	(19,460)	(18,475)	(14,465)
Funded status – shortfall	25,430	26,975	23,935
Amounts recorded in the Consolidated Balance Sheets for the plans:
Other liabilities — accrued pension obligation	25,430	26,975	23,935
Stockholders’ equity — deferred actuarial loss	$ (5,738)	$ (5,861)	$ (5,797)