Employee Benefit Plans (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Pension Plan [Member]
Summary of net periodic pension cost
Service cost - benefits earned during the year	$ 1,516	$ 1,400	$ 1,647
Interest cost on accumulated benefit obligation	2,607	2,493	2,605
Expected return on plan assets	(2,858)	(2,618)	(2,146)
Net amortization and deferral	65	64	490
Net periodic pension cost	1,330	1,339	2,596
Supplementary Pension Plan [Member]
Summary of net periodic pension cost
Service cost - benefits earned during the year	196	320	216
Interest cost on accumulated benefit obligation	485	533	450
Expected return on plan assets	0	0	0
Net amortization and deferral	88	131	74
Net periodic pension cost	$ 769	$ 984	$ 740