Income Taxes - Classification of Net Deferred Income Tax Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Classification of Deferred Income Tax Assets and Liabilities [Line Items]
Document Period End Date	Dec. 31, 2018
Net deferred income tax (liabilities)	$ (16,916)
Net deferred income tax assets		$ 12,252
Other noncurrent assets
Balance Sheet Classification of Deferred Income Tax Assets and Liabilities [Line Items]
Net deferred income tax assets	49,937	76,750
Other noncurrent liabilities
Balance Sheet Classification of Deferred Income Tax Assets and Liabilities [Line Items]
Net deferred income tax (liabilities)	$ (66,853)	$ (64,498)