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, 2015	Jun. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balances - Liabilities	$ 4,572	$ 9,176
Total loss included in accumulated other comprehensive loss	377	1,068
Settlements	(2,947)	(2,985)
Ending balances - Liabilities	$ 2,002	$ 7,259