Summary of Activity Related to Liability for Special Charges (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Special Charges [Line Items]
Net non-cash expense reversals	$ 300
Special charges remaining liability	11,560	[1]	$ 11,813	$ 18,613
Total expected payments to special charges, amount expected to be paid in 2017	6,100
Total expected payments to special charges, amount expected to be paid in 2018	2,600
Total expected payments to special charges, amount expected to be paid in 2019	1,200
Total expected payments to special charges, amount expected to be paid in 2020	400
Total expected payments to special charges, amount expected to be paid from 2021 to 2025	1,300
Selling, General and Administrative Expenses
Special Charges [Line Items]
Expected sublease income	$ 200		$ 400

[1] Of the $11.6 million remaining liability for special charges, $6.1 million is expected to be paid in 2017, $2.6 million is expected to be paid in 2018, $1.2 million is expected to be paid in 2019, $0.4 million is expected to be paid in 2020 and the remaining balance of $1.3 million is expected to be paid from 2021 to 2025