Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities
Net income	$ 64,031	$ 86,106
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	35,146	33,333
Provision for doubtful accounts	28	12
Deferred income taxes	3,865	7,469
Excess tax benefits from stock based compensation	(67)	(1,292)
Gain on disposal or impairment of assets	(56)	(12)
Foreign currency transaction loss, net	2	31
Stock compensation expense	4,519	4,051
Changes in operating assets and liabilities:
Trade accounts and other receivables	(52,708)	(5,499)
Inventories	10,901	2,016
Prepaid expenses and other current assets	(3,772)	(2,679)
Long-term prepaid expenses	1,973	1,306
Accounts payable	2,460	(25,819)
Accrued expenses	3,730	(9,811)
Accrued income taxes, net	1,185	9,302
Net cash provided by operating activities	71,237	98,514
Investing activities
Capital expenditures	(61,186)	(64,124)
Net cash used in investing activities	(61,186)	(64,124)
Financing activities
Proceeds from bank borrowings		10,000
Repayments on bank borrowings		(10,000)
Net proceeds from stock based compensation		54
Dividends paid	(19,427)	(17,328)
Purchase of common stock	(6,821)	(7,655)
Excess tax benefits from stock based compensation	67	1,292
Net cash used in financing activities	(26,181)	(23,637)
Effect of exchange rate changes on cash	(748)	(2)
Net (decrease) increase in cash and cash equivalents	(16,878)	10,751
Cash and cash equivalents at beginning of period	90,635	41,270
Cash and cash equivalents at end of period	73,757	52,021
Supplemental cash flow information
Interest paid	3	76
Income taxes paid	$ 24,909	$ 25,870