Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012 Plans	Jun. 30, 2011	Jun. 30, 2012 Plans	Jun. 30, 2011
Compensation and Retirement Disclosure [Abstract]
Number of frozen defined benefit plans	1		1
Components of net periodic pension expense:
Interest cost	$ 552	$ 603	$ 1,104	$ 1,206
Expected return on plan assets	(662)	(644)	(1,324)	(1,288)
Amortization of net loss	244	152	487	182
Total pension expense	$ 134	$ 111	$ 267	$ 100