Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Unfunded post retirement benefits plan
Benefit obligation at beginning of year	$ 1,674	$ 1,073	$ 783
Interest cost	69	56	43
Service cost	88	49	34
Actual claim expense	(184)	(262)	(167)
Actuarial loss	577	758	380
Benefit obligation at end of year	$ 2,224	$ 1,674	$ 1,073