Benefit Plans - Funded Status of Plan (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Change in Projected Benefit Obligation
Projected benefit obligation, beginning of period			$ 32,474	$ 32,820	$ 32,820
Service cost	$ 250	$ 300	499	600	1,200
Interest cost	348	$ 310	696	621	1,242
Actuarial loss			0		(2,166)
Benefits paid			(391)		(622)
Projected benefit obligation, end of period	33,278		33,278		32,474
Change in Plan Assets
Plan assets at fair value, beginning of period			0	$ 0	0
Company contributions			391		622
Benefits paid			(391)		(622)
Plan assets at fair value, end of period	0		0		0
Unfunded Status of the Plan	$ 33,278		$ 33,278		$ 32,474