Lease Accounting - Schedule of Impact of Changes Made to the Consolidated Balance Sheet from the Adoption of ASC 842 (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Operating lease assets	$ 23,948
Other current liabilities	2,843		$ 119
Long-term operating lease liabilities	23,006
Other long-term liabilities	1,643		$ 2,825
ASC 842 [Member]
Lessee Lease Description [Line Items]
Operating lease assets	$ 24,800	$ 24,771
Other current liabilities		2,508
Long-term operating lease liabilities		23,805
Other long-term liabilities		1,402
ASC 842 [Member] | Adjustments due to ASC 842 [Member]
Lessee Lease Description [Line Items]
Operating lease assets		24,771
Other current liabilities		2,389
Long-term operating lease liabilities		23,805
Other long-term liabilities		$ (1,423)