Spin-off of Apergy Corporation (Detail) € in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2019 EUR (€)	May 09, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Cash Equivalents				$ 10,400
Current assets		$ 17,441
Assets held for sale	$ 0	44,210
Current liabilities		12,947
Total liabilities of discontinued operations	0	$ 20,581
Less: Cash received from Apergy Corporation	700,000
Cash received from Apergy, net of cash distributed	689,600
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
Assets held for sale				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
Separation of Apergy	33,000
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
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%
Debt Instrument, Unused Borrowing Capacity, Amount	$ 415,000