Pension, Postretirement and Postemployment Benefits (Details) (Pension Benefits [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	$ 20,628	$ 18,865
Remeasurement	1,517
Interest cost	1,198	1,116	1,093
Actuarial loss (gain)	3,975	1,289
Benefit payments	(659)	(642)
Benefit obligation at end of year	26,659	20,628	18,865
Change in plan assets:
Fair value of plan assets at beginning of year	15,219	14,058
Actual (loss) return on plan assets	480	1,364
Employer contribution	1,312	439
Benefit payments	(659)	(642)
Fair value of plan assets at end of year	16,352	15,219	14,058
Funded status:
Underfunded status at end of year	(1,030)	(5,409)
Amounts recognized in consolidated balance sheets:
Other long-term liabilities	(10,307)	(5,409)
Components of net periodic benefit cost (recognized in our consolidated statements of income):
Interest cost	1,198	1,116	1,093
Expected return on plan assets	(1,008)	(909)	(794)
Recognized net actuarial loss	628	457	545
Net periodic benefit cost	$ 818	$ 664	$ 844
Weighted-average assumptions:
Weighted-average discount rate	4.25%	5.50%	6.00%
Expected long-term rate of return on plan assets	6.50%	6.50%	6.50%