Discontinued Operations (Summary Of Financial Information That Has Been Segregated From Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Discontinued operations:
Net (loss) income from discontinued operations	$ (17,836)	$ (876)	$ (2,169)	$ (30,156)	$ (2,689)	$ (1,614)	$ (15,317)	$ (1,000)	$ (51,037)	$ (20,620)	$ 13,981
Assets:
Assets held for sale	43,900				115,972				43,900	115,972
Discontinued Operations, Held-for-sale | Drilling Technologies
Discontinued operations:
Revenue									27,627	52,112	113,302
Cost of revenue									(18,667)	(35,410)	(67,651)
Selling, general and administrative									(15,285)	(21,049)	(22,870)
Depreciation and amortization									(1,714)	(3,240)	(3,343)
Research and development									(64)	(202)	(172)
Gain (loss) on disposal of long-lived assets									103	17	(244)
Impairment of inventory and long-lived assets									(36,522)	(19,568)	0
(Loss) income from operations									(44,522)	(27,340)	19,022
Other expense									(412)	(259)	(227)
Loss on sale of assets									(1,199)	0	0
Loss on write-down of assets held for sale									(18,971)	0	0
(Loss) income before income taxes									(65,104)	(27,599)	18,795
Income tax benefit (expense)									23,661	9,675	(6,858)
Net (loss) income from discontinued operations									(41,443)	(17,924)	11,937
Assets:
Accounts receivable, net	5,072				7,712				5,072	7,712
Inventories	9,078				22,388				9,078	22,388
Other current assets	278				315				278	315
Long-term receivable	0				0				0	0
Property and equipment, net	11,277				27,837				11,277	27,837
Goodwill	15,333				15,333				15,333	15,333
Other intangible assets, net	7,395				17,648				7,395	17,648
Assets held for sale	48,433				91,233				48,433	91,233
Valuation allowance	(18,971)				0				(18,971)	0
Assets held for sale, net	29,462				91,233				29,462	91,233
Liabilities:
Accounts payable	2,472				1,441				2,472	1,441
Accrued liabilities	1,190				1,897				1,190	1,897
Liabilities held for sale	3,662				3,338				3,662	3,338
Discontinued Operations, Held-for-sale | Production Technologies
Discontinued operations:
Revenue									8,292	12,281	16,003
Cost of revenue									(7,881)	(10,179)	(9,459)
Selling, general and administrative									(3,790)	(4,158)	(3,040)
Depreciation and amortization									(584)	(658)	(254)
Research and development									(888)	(596)	(17)
Gain (loss) on disposal of long-lived assets									(50)	3	14
Impairment of inventory and long-lived assets									(3,913)	(804)	0
(Loss) income from operations									(8,814)	(4,111)	3,247
Other expense									(96)	(40)	(28)
Loss on sale of assets									0	0	0
Loss on write-down of assets held for sale									(6,161)	0	0
(Loss) income before income taxes									(15,071)	(4,151)	3,219
Income tax benefit (expense)									5,477	1,455	(1,175)
Net (loss) income from discontinued operations									(9,594)	(2,696)	$ 2,044
Assets:
Accounts receivable, net	1,784				5,974				1,784	5,974
Inventories	8,115				12,234				8,115	12,234
Other current assets	370				232				370	232
Long-term receivable	4,179				0				4,179	0
Property and equipment, net	3,978				4,070				3,978	4,070
Goodwill	1,689				1,689				1,689	1,689
Other intangible assets, net	484				540				484	540
Assets held for sale	20,599				24,739				20,599	24,739
Valuation allowance	(6,161)				0				(6,161)	0
Assets held for sale, net	14,438				24,739				14,438	24,739
Liabilities:
Accounts payable	914				782				914	782
Accrued liabilities	385				517				385	517
Liabilities held for sale	$ 1,299				$ 1,299				$ 1,299	$ 1,299