Note 14 - Guarantor Subsidiaries (Details) - Condensed Consolidating Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	$ 21,419	$ 30,383
Cash flows from investing activities:
Additions to properties, plants, and equipment	(26,958)	(26,867)
Cash flows from financing activities:
Effect of exchange rates on cash	(2,560)	(1,698)
Changes in cash and cash equivalents	(13,434)	(4,533)
Cash and cash equivalents at beginning of period	209,665	212,175
Cash and cash equivalents at end of period	196,231	207,642
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	(30,032)	(23,615)
Cash flows from investing activities:
Other investing activities		2,570
Cash flows from financing activities:
Other financing activity	30,032	21,045
Consolidated [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	21,419	30,383
Cash flows from investing activities:
Additions to properties, plants, and equipment	(26,958)	(26,867)
Other investing activities	(922)	(2,485)
Cash flows from financing activities:
Dividends paid to stockholders	(1,062)	(995)
Payments on debt	(2,347)	(2,403)
Other financing activity	(1,004)	(468)
Effect of exchange rates on cash	(2,560)	(1,698)
Changes in cash and cash equivalents	(13,434)	(4,533)
Cash and cash equivalents at beginning of period	209,665	212,175
Cash and cash equivalents at end of period	196,231	207,642
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	15,726	31,570
Cash flows from investing activities:
Additions to properties, plants, and equipment	(424)	(383)
Other investing activities		(2,570)
Cash flows from financing activities:
Dividends paid to stockholders	(1,062)	(995)
Borrowings on debt		(316)
Payments on debt		312
Other financing activity	(15,841)	(16,637)
Changes in cash and cash equivalents	(1,601)	10,981
Cash and cash equivalents at beginning of period	146,885	126,271
Cash and cash equivalents at end of period	145,284	137,252
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	15,823	23,937
Cash flows from investing activities:
Additions to properties, plants, and equipment	(18,163)	(13,628)
Other investing activities	25	(57)
Cash flows from financing activities:
Borrowings on debt		316
Payments on debt	(1,901)	(2,715)
Other financing activity	6,349	(4,463)
Changes in cash and cash equivalents	2,133	3,390
Cash and cash equivalents at beginning of period	33,824	40,009
Cash and cash equivalents at end of period	35,957	43,399
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows from operating activities	19,902	(1,509)
Cash flows from investing activities:
Additions to properties, plants, and equipment	(8,371)	(12,856)
Other investing activities	(947)	(2,428)
Cash flows from financing activities:
Payments on debt	(446)
Other financing activity	(21,544)	(413)
Effect of exchange rates on cash	(2,560)	(1,698)
Changes in cash and cash equivalents	(13,966)	(18,904)
Cash and cash equivalents at beginning of period	28,956	45,895
Cash and cash equivalents at end of period	$ 14,990	$ 26,991