Fair Value Measurements Pre-Tax Gain (Loss) Recognized From Derivative Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Exchange Traded Options [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	$ 1,763	$ 0	$ 609	$ 0
Swap [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	1,201	0	1,201	0
Change In Value Of Warrants [Member] | Warrant [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	3,313	140	(1,709)	1,717
Change in Value of Contingent Consideration [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	(9,495)	2,297	(14,424)	4,762
Loss On Derivative Instruments, Net [Member] | Future [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	1,338	(340)	762	(191)
Loss On Derivative Instruments, Net [Member] | Forward Contracts [Member]
Derivatives not designated as hedges, Gain (loss) recognized in income	$ 0	$ (625)	$ 0	$ (1,141)