Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in plan assets
Plan assets at fair value at December 31	$ 17,281	$ 16,731
Pension Benefits [Member]
Change in benefit obligation
Benefit obligation at January 1	21,491	24,417
Service cost	227	198	191
Interest cost	970	882	934
Actuarial (gain) loss	4,451	(2,795)
Assumed administrative expenses	(227)	(198)
Benefits paid	(1,049)	(1,013)
Benefit obligation at December 31	25,863	21,491	24,417
Change in plan assets
Plan assets at January 1	16,731	14,894
Actual return on plan assets	888	2,313
Administrative expenses	(227)	(198)
Employer contributions	938	735
Benefits paid	(1,049)	(1,013)
Plan assets at fair value at December 31	17,281	16,731	14,894
Funded status
Benefit obligation in excess of plan assets at December 31	(8,582)	(4,760)
Postretirement Benefits [Member]
Change in benefit obligation
Benefit obligation at January 1	75	111
Service cost	0	1	1
Interest cost	3	4	4
Plan amendments		(31)
Actuarial (gain) loss	(1)	(6)
Benefits paid	0	(4)
Benefit obligation at December 31	77	75	111
Change in plan assets
Benefits paid	0	(4)
Funded status
Benefit obligation in excess of plan assets at December 31	$ (77)	$ (75)