Postretirement Benefits (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in benefit obligation:
Benefit obligation at beginning of year	$ 3,117	$ 2,497
Service cost	88	73	73
Interest cost	120	128	146
Participant contribution	16	14
Actuarial (gains) / losses	(148)	537
Acquisition	60	0
Benefits paid	(113)	(132)
Benefit obligation at end of year	3,140	3,117	2,497
Change in fair value of plan assets:
Balance at beginning of year	0	0
Employer contribution	97	118
Participant contribution	16	14
Benefits paid	(113)	(132)
Balance at end of year	0	0	0
Funded status at end of year	$ (3,140)	$ (3,117)