Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010
Cash flow from operating activities:
Net income	$ 25,994		$ 22,065
Adjustments to reconcile from net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion, and amortization	19,731		17,022
Other non-cash charges	2,891		3,655
Changes in assets and liabilities, net of effects of acquisitions:
Decrease (increase) in current assets	(57,469)		(49,570)
Decrease (increase) in noncurrent assets	(843)		(1,832)
Increase (decrease) in current liabilities	22,016		14,667
Increase (decrease) in noncurrent liabilities	1,528		843
Net cash provided by (used in) operating activities	13,848		6,850
Cash flow from investing activities:
Capital expenditures	(24,800)		(25,939)
Investments in and advances to affiliates and joint ventures	(1,276)		(1,985)
Other	1,718		1,493
Net cash (used in) investing activities	(24,358)		(26,431)
Cash flow from financing activities:
Net change in outstanding debt	4,530		17,808
Proceeds from sales of treasury stock	6,619		2,904
Dividends	(11,351)		(11,149)
Excess tax benefits from stock-based compensation	651		164
Net cash provided by (used in) financing activities	449		9,727
Effect of foreign currency rate changes on cash	727		(779)
Net increase (decrease) in cash and cash equivalents	(9,334)		(10,633)
Cash and cash equivalents at beginning of period	27,262	[1]	27,669
Cash and cash equivalents at end of period	$ 17,928		$ 17,036

[1] Condensed from audited financial statements.