CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities
Net income	$ 41,444	$ 33,883
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	23,706	23,394
Provision for doubtful accounts	246	28
Deferred income taxes	2,485	2,609
Excess tax benefits from stock based compensation	(372)	(67)
Gain on disposal of assets	(191)	(40)
Foreign currency transaction (gain) loss, net	(26)	31
Stock compensation expense	4,454	3,189
Changes in operating assets and liabilities:
Trade accounts and other receivables	(6,726)	(6,540)
Inventories	(2,074)	(2,372)
Prepaid expenses and other current assets	(3,316)	(3,466)
Long-term other assets	500	1,711
Accounts payable	4,348	(4,845)
Accrued expenses	(4,875)	(6,748)
Accrued income taxes, net	(2,099)	(4,054)
Net cash provided by operating activities	57,504	36,713
Investing activities
Capital expenditures	(85,487)	(31,169)
Net cash used in investing activities	(85,487)	(31,169)
Financing activities
Dividends paid	(13,876)	(12,503)
Purchase of common stock	(5,779)	(6,821)
Excess tax benefits from stock based compensation	372	67
Net cash used in financing activities	(19,283)	(19,257)
Effect of exchange rate changes on cash	(605)	(899)
Net decrease in cash and cash equivalents	(47,871)	(14,612)
Cash and cash equivalents at beginning of period	94,250	90,635
Cash and cash equivalents at end of period	46,379	76,023
Supplemental cash flow information
Interest paid	17	3
Income taxes paid	$ 19,983	$ 17,153