Benefit Plans - Funded Status of Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Change in Projected Benefit Obligation
Projected benefit obligation, beginning of period			$ 32,474	$ 32,820	$ 32,820
Service cost	$ 300	$ 300	749	900	1,200
Interest cost	348	$ 310	1,045	931	1,242
Actuarial gain			0		(2,166)
Benefits paid			(585)		(622)
Projected benefit obligation, end of period	33,683		33,683		32,474
Change in Plan Assets
Plan assets at fair value, beginning of period			0	$ 0	0
Company contributions			585		622
Benefits paid			(585)		(622)
Plan assets at fair value, end of period	0		0		0
Unfunded Status of the Plan	$ 33,683		$ 33,683		$ 32,474