Incentive Plans - Summary of Impact of LFI and Other Similar Deferred Compensation Arrangements (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation [Abstract]
Amortization, net of forfeitures	$ 85,563	$ 82,359	$ 62,197
Change in the fair value of underlying investments	(3,827)	7,326	14,099
Total	$ 81,736	$ 89,685	$ 76,296

Amount of expense recognized from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments), awarded to key employees or individuals. Excludes amount related to plans that cover generally all employees (for example, but not limited to, qualified pension plans).

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration