Other Postretirement Benefits (Changes in the Accumulated Postretirement Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at	$ 1,961	$ 2,179	$ 2,478
Service cost	0	0	0
Interest cost	66	88	80
Actuarial (gains) losses	(39)	9	(58)
Benefits paid	(303)	(315)	(321)
Projected benefit obligation at	1,685	1,961	2,179
Fair value of plan assets	0	0	0
Under funded status	(1,685)	(1,961)	(2,179)
Unamortized prior service cost	10	24	39
Unrecognized actuarial gain	(218)	(179)	(188)
Net amount recognized	(1,893)	(2,116)	(2,328)
Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at	8,202	5,900	5,954
Service cost	26	16	16
Interest cost	300	255	203
Plan amendments	0	0	603
Actuarial (gains) losses	(29)	2,387	(553)
Benefits paid	(350)	(356)	(323)
Projected benefit obligation at	8,149	8,202	5,900
Fair value of plan assets	0	0	0
Under funded status	(8,149)	(8,202)	(5,900)
Unamortized prior service cost	515	559	603
Unrecognized actuarial gain	3,736	3,962	1,653
Net amount recognized	$ (3,898)	$ (3,681)	$ (3,644)