Fair Value of Financial Instruments Unrealized Gains Included in Earnings Attributable to Level 3 Assets Held (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	$ 32,399	$ 39,560
Unrealized gains (losses) attributable to noncontrolling interests	(158)	2,914
Equity warrant assets | Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	32,576	36,516
Non-marketable securities | Fair value accounting | Other venture capital investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Unrealized Gains (Losses) [Line Items]
Unrealized gains included in earnings attributable to Level 3 assets still held	$ (177)	$ 3,044