Spin-off of Apergy Corporation Spin-off of Apergy Corporation (Detail) € in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 EUR (€)	May 09, 2018 USD ($)	Dec. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Cash Equivalents				$ 10,357
Current assets					$ 417,678
Total Assets of Discontinued Operations	$ 0				1,865,553
Current liabilities					156,921
Total Liabilities of Discontinued Operations	0				$ 264,253
Less: Cash received from Apergy Corporation	700,000
Cash received from Apergy, net of cash distributed	689,643	$ 0
Separation of Apergy	(906,815)
Stock repurchase program (dollar value of planned repurchases)	1,000,000
Apergy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Cash Equivalents				10,357
Current assets				462,620
Non-current assets				1,438,760
Total Assets of Discontinued Operations				1,911,737
Current liabilities				185,354
Noncurrent liabilities				119,568
Total Liabilities of Discontinued Operations				304,922
Net assets distributed to Apergy Corporation				1,606,815
Less: Cash received from Apergy Corporation	$ 700,000
Net distribution to Apergy Corporation				$ 906,815
Note due 2026 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Debt Instrument, Face Amount | €			€ 600,000
Debt Instrument, Interest Rate, Stated Percentage	1.25%		1.25%
Note due 2026 [Member] | Apergy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Debt Instrument, Face Amount	$ 300,000
Debt Instrument, Interest Rate, Stated Percentage	6.375%		6.375%
Debt Instrument, Unused Borrowing Capacity, Amount	$ 415,000
AOCI Attributable to Parent [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Separation of Apergy	$ 32,928