Reconciliation of Beginning and Ending Balance for Liabilities Measured at Fair Value on Recurring Basis Unobservable Inputs (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balances - Liabilities	$ 373	$ 4,572
Total loss included in accumulated other comprehensive loss	71	377
Settlements	$ (444)	(2,947)
Ending balances - Liabilities		$ 2,002