Retirement Plan (Changes in Benefit Obligation and Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan's benefit obligation - beginning of year	$ 23,633	$ 15,715
Defined Benefit Plan, Service Cost	1,694	895	$ 1,112
Interest cost	819	638	665
Defined Benefit Plan, Contributions by Plan Participants	593	573
Defined Benefit Plan, Plan Amendments	0	3,383
Benefits paid	(2,260)	(1,533)
Actuarial loss	(3,278)	3,962
Pension plan's benefit obligation - end of year	21,201	23,633	15,715
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets - beginning of year	0	0
Benefits paid	(2,260)	(1,533)
Employer contributions	1,667	960
Defined Benefit Plan, Contributions by Plan Participants	593	573
Fair value of plan assets - end of year	0	0	$ 0
Defined Benefit Plan, Funded Status of Plan	(21,201)	(23,633)
Accrued post-retirement plan liability	(21,201)	(23,633)
Post-retirement plan accumulated other comprehensive loss	(1,613)	(5,074)
Post-retirement plan accumulated other comprehensive loss prior service credit	35,937	39,419
Post-retirement plan accumulated other comprehensive loss	$ 34,324	$ 34,345