CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 64.7	$ 61.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	42.6	39.1
Amortization	2.3	2.1
Loss on debt extinguishment	0	0.2
Stock-based compensation	8.9	10.4
Other non-cash items, net	(1.9)	(2.7)
Changes in assets and liabilities	(43.6)	(12.6)
Net cash provided by operating activities	73.0	98.4
Cash flows from investing activities:
Capital expenditures	(56.2)	(83.8)
Purchases of short-term investments	(9.3)	(8.8)
Sales and maturities of short-term investments	8.3	13.7
Other, net	0.2	(3.0)
Net cash used in investing activities	(57.0)	(81.9)
Cash flows from financing activities:
Borrowings under revolving credit agreements	182.9	178.3
Repayments under revolving credit agreements	(192.9)	(171.6)
Issuance of long-term debt	0	43.3
Repayments of long-term debt	(1.1)	(29.3)
Dividend payments	(14.1)	(13.1)
Excess tax benefit from employee stock plans	3.7	1.1
Shares repurchased for employee tax withholdings	(4.1)	(5.2)
Proceeds from stock option exercises	5.2	10.7
Employee stock purchase plan contributions	1.5	1.1
Contingent consideration payments	(0.1)	0
Net cash (used in) provided by financing activities	(19.0)	15.3
Effect of exchange rates on cash	(0.3)	(3.1)
Net (decrease) increase in cash and cash equivalents	(3.3)	28.7
Cash and cash equivalents at beginning of period	230.0	161.9
Cash and cash equivalents at end of period	$ 226.7	$ 190.6