CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flow from operating activities:
Net income	$ 27.0	$ 34.8
Adjustments to reconcile from net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion, and amortization	24.3	21.8
Other non-cash charges	5.3	7.4
Changes in assets and liabilities, net of effects of acquisitions:
Decrease (increase) in current assets	(48.3)	(25.6)
Decrease (increase) in noncurrent assets	(2.1)	(1.2)
Increase (decrease) in current liabilities	21.1	0.3
Increase (decrease) in noncurrent liabilities	1.7	1.4
Net cash provided by (used in) operating activities	29.0	38.9
Cash flow from investing activities:
Capital expenditures	(44.1)	(32.2)
(Increase) decrease in investments in and advances (to) from affiliates and joint ventures	(4.9)	0.1
Proceeds from sale of land and depreciable assets	0.5	1.4
Other	1.3	0.8
Net cash (used in) investing activities	(47.2)	(29.9)
Cash flow from financing activities:
Net change in outstanding debt	21.6	(9.6)
Proceeds from sales of treasury stock	4.4	3.9
Dividends paid	(12.9)	(11.5)
Excess tax benefits from stock-based compensation	0.1	0.2
Contribution from noncontrolling partner	0.1	0
Net cash provided by (used in) financing activities	13.3	(17.0)
Effect of foreign currency rate changes on cash	0	0.7
Net increase (decrease) in cash and cash equivalents	(4.9)	(7.3)
Cash and cash equivalents at beginning of period	40.0	24.1
Cash and cash equivalents at end of period	$ 35.1	$ 16.8