Employee Benefit Plans - Changes in Obligations and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Change in plan assets:
Fair value of plan assets at beginning of year	$ 9,331	$ 9,368
Actual return on plan assets	1,218	612
Employer contribution	0	0
Benefits paid	(390)	(649)
Fair value of plan assets at end of year	10,159	9,331
Change in benefit obligation:
Benefit obligation at beginning of year	10,609	10,174
Interest cost	438	465
Actuarial loss	71	483
Effect of change in assumptions	1,073	136
Benefits paid	(390)	(649)
Benefit obligation at end of year	11,801	10,609
Funded status (plan assets less benefit obligation)	(1,642)	(1,278)
Amounts recognized in accumulated other comprehensive loss, net of tax, consists of:
Accumulated net actuarial loss	4,838	3,812
Accumulated prior service benefit	0	0
Amount recognized, end of year	$ 4,838	$ 3,812