Schedule of Share-based Compensation Expense (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Special charges	$ 0	$ 5,347	$ 0	$ 14,711
Equity award expense acceleration
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Special charges		$ 200
Share based awards, value of shares forfeited				$ 1,200