Schedule of Share-based Compensation Expense (Parenthetical) (Detail) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Special charges	$ 1,628,000	$ 5,347,000	$ 9,364,000	$ 0	$ 16,339,000	$ 38,414,000
Equity award expense acceleration
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Special charges					200,000
Share based awards, value of shares forfeited					1,200,000
Option expense acceleration
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Special charges					100,000
Options, value of shares forfeited					$ 200,000