Special Charges - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Other Income And Expenses [Abstract]
Special charges	$ 0	$ 6,811
Special charges liability	$ 11,519	11,519	$ 11,813
Total expected payments to special charges, amount expected to be paid in 2016		1,900
Total expected payments to special charges, amount expected to be paid in 2017		4,100
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 from 2020 to 2026		$ 1,700