Discontinued Operations (Summary Of Financial Information That Has Been Segregated From Continuing Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Discontinued Operations:
Net loss from discontinued operations	$ (11,235)	$ (30,156)
Assets:
Assets held for sale	27,891		$ 43,900
Liabilities:
Loss from discontinued operations, net of tax	(11,235)	(30,156)
Drilling Technologies | Discontinued Operations, Held-for-sale
Discontinued Operations:
Revenue	6,797	6,456
Cost of revenue	(4,655)	(5,431)
Selling, general and administrative	(3,031)	(4,665)
Depreciation and amortization	0	(748)
Research and development	0	(42)
Gain (loss) on disposal of long-lived assets	73	0
Impairment of inventory and long-lived assets	0	(36,522)
Loss from operations	(816)	(40,952)
Other expense	(71)	(175)
Loss on write-down of assets held for sale	(6,560)	0
Loss before income taxes	(7,447)	(41,127)
Income tax benefit	2,713	14,499
Net loss from discontinued operations	(4,734)	(26,628)
Assets:
Accounts receivable, net	5,328		5,072
Inventories	9,059		9,078
Other current assets	272		278
Long-term receivable	0		0
Property and equipment, net	11,352		11,277
Goodwill	15,333		15,333
Other intangible assets, net	7,398		7,395
Assets held for sale	48,742		48,433
Valuation allowance	(25,531)		(18,971)
Assets held for sale, net	23,211		29,462
Liabilities:
Accounts payable	3,162		2,472
Accrued liabilities	464		1,190
Liabilities held for sale	3,626		3,662
Production Technologies | Discontinued Operations, Held-for-sale
Discontinued Operations:
Revenue	3,153	2,021
Cost of revenue	(2,483)	(1,911)
Selling, general and administrative	(873)	(1,211)
Depreciation and amortization	0	(148)
Research and development	(271)	(267)
Impairment of inventory and long-lived assets	0	(3,913)
Loss from operations	(474)	(5,429)
Other expense	(36)	(20)
Loss on write-down of assets held for sale	(9,717)	0
Loss before income taxes	(10,227)	(5,449)
Income tax benefit	3,726	1,921
Net loss from discontinued operations	(6,501)	$ (3,528)
Assets:
Accounts receivable, net	1,993		1,784
Inventories	7,768		8,115
Other current assets	381		370
Long-term receivable	4,179		4,179
Property and equipment, net	4,059		3,978
Goodwill	1,689		1,689
Other intangible assets, net	489		484
Assets held for sale	20,558		20,599
Valuation allowance	(15,878)		(6,161)
Assets held for sale, net	4,680		14,438
Liabilities:
Accounts payable	834		914
Accrued liabilities	178		385
Liabilities held for sale	$ 1,012		$ 1,299