Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012 Plans	Sep. 30, 2011	Sep. 30, 2012 Plans	Sep. 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	$ 1,656	$ 1,809
Expected return on plan assets	(662)	(644)	(1,986)	(1,932)
Amortization of net loss	244	91	731	273
Total pension expense	$ 134	$ 50	$ 401	$ 150