Employee Benefit Plans Defined benefit pension plan obligations and funded status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at beginning of year	$ 17,177	$ 18,103
Interest cost	701	680	$ 757
Actuarial loss (gain)	544	(809)
Benefits paid	(735)	(797)
Projected benefit obligation at end of year	17,687	17,177	18,103
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	15,717	17,300
Actuarial gain (loss) on plan assets	899	(786)
Employer contributions	750	0
Benefits paid	(735)	(797)
Fair value of plan assets at end of year	16,631	15,717	$ 17,300
Net liability for pension benefits	(1,056)	(1,460)
Accumulated benefit obligation at December 31	$ 17,687	$ 17,177