Employee Benefit Plans - Change in PBO and Assets and Reconciliations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent liabilities	$ (29,800)	$ (31,905)
Pension
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	87,986	81,752
Service cost	0	0	$ 1,307
Interest cost	3,021	3,259	3,474
Actuarial (gain) loss	(8,160)	6,123
Benefits paid	(3,288)	(3,148)
Projected benefit obligation at end of year	79,559	87,986	81,752
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	57,377	51,114
Actual return on plan assets	(4,638)	9,909
Employer contributions	2,829	90
Benefits paid	(4,002)	(3,148)
Other expense	(617)	(588)
Fair value of plan assets at end of year	50,949	57,377	51,114
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Net accrued benefit cost	(28,610)	(30,609)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities	(86)	(92)
Noncurrent liabilities	(28,524)	(30,517)
Net amount recognized	(28,610)	(30,609)
Postretirement
Change in Projected Benefit Obligation
Projected benefit obligation at beginning of year	1,420	1,285
Service cost	7	6	4
Interest cost	38	53	42
Actuarial (gain) loss	(149)	89
Benefits paid	(13)	(13)
Projected benefit obligation at end of year	1,303	1,420	1,285
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	13	13
Benefits paid	(13)	(13)
Other expense	0	0
Fair value of plan assets at end of year	0	0	$ 0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Net accrued benefit cost	(1,303)	(1,420)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Current liabilities	(27)	(32)
Noncurrent liabilities	(1,276)	(1,388)
Net amount recognized	$ (1,303)	$ (1,420)