Employee Benefit Plans (Details 5) (Pension Plan, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Plan
Service cost - benefits earned during the period	$ 1,835	$ 1,782	$ 1,754
Interest cost on projected benefit obligation	1,451	1,638	1,555
Expected return on plan assets	(1,969)	(1,716)	(1,479)
Net amortization and deferral	559	395	465
Net periodic pension cost	$ 1,876	$ 2,099	$ 2,295