Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Retirement Benefits [Abstract]
Defined benefit plan, employer contributions			$ 1,000	$ 2,500
Defined benefit plan, expected future employer contributions, remainder of fiscal year	$ 0		0
Defined contribution plan, compensation expense	$ 1,000	$ 900	$ 1,900	$ 2,100