CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
Net cash provided by operating activities	$ 4,861	$ 40,130
Cash flows from investing activities:
Capital expenditures	(19,465)	(73,836)
Grants received for capital expenditures		236
Proceeds from sale of business	105,067	20,500
Proceeds from sale of assets	1,098	2
Net cash provided by (used in) investing activities	86,700	(53,098)
Cash flows from financing activities:
Net payments of commercial paper	(40,700)	(8,650)
Borrowings under credit agreement	65,000	3,000
Payments under credit agreement	(70,500)	(3,000)
Issuances of notes payable		50,000
Payments under industrial development bond agreement		(19,000)
Proceeds from stock option exercises	104
Dividends paid	(2,963)	(2,958)
Net cash (used in) provided by financing activities	(49,059)	19,392
Net increase in cash and cash equivalents	42,502	6,424
Cash and cash equivalents, beginning of period	4,044	26,661
Cash and cash equivalents, end of period	$ 46,546	$ 33,085