Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Taxes
Unrecognized tax benefits	$ 5,000
Unrecognized tax benefits would impact the effective tax rate	4,500
Interest accrued	$ 800
Effective tax rate from operations	6.10%	(44.80%)
Benefit from income taxes	$ 510	$ 518
Effective U.S corporate tax rate	21.00%		35.00%
Provision for transition tax	$ 37,200			$ 37,200
Transition tax paid	$ 8,300			8,300
Transition tax last payment, year	2025
Retained earnings	$ 541,228			549,134
Minimum
Income Taxes
Undistributed foreign earnings	197,400
Other Long-term Liabilities
Income Taxes
Transition tax	28,900			28,900
U.S
Income Taxes
Cash and cash equivalents and short-term investments	$ 124,100			173,600
U.S | Earliest Tax Year
Income Taxes
Tax years subject to examination	2014
Italy | Earliest Tax Year
Income Taxes
Tax years subject to examination	2013
Poland | Earliest Tax Year
Income Taxes
Tax years subject to examination	2014
Spain | Earliest Tax Year
Income Taxes
Tax years subject to examination	2015
United Kingdom | Earliest Tax Year
Income Taxes
Tax years subject to examination	2016
Germany | Earliest Tax Year
Income Taxes
Tax years subject to examination	2016
Foreign
Income Taxes
Cash and cash equivalents and short-term investments	$ 427,000			402,500
Retained earnings				$ 397,400
Offshore receipts in respect of intangible property legislation tax payments percentage	20.00%