Accumulated Other Comprehensive Income - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	$ 11,844	$ 2,180
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax	788	3,369
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(228)	(1,257)
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(2,398)	(3,188)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	289	(5,866)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	69	1,942
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	(533)
Benefit plan liabilities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(3,329)	(2,084)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	326	329
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	(1,961)	$ (486)
UNITED KINGDOM
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	$ (6,288)