Summary of Major Types of Costs, Cumulative Costs Incurred and Total Cost Expected Associated With Restructuring Activities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 86	$ 11,578	$ 261	$ 11,578
Cumulative Costs Incurred To Date	14,993		14,993
Total Expected Plan Costs	15,070		15,070
Severance and related employee benefits
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	13,162		13,162
Total Expected Plan Costs	13,162		13,162
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	1,159		1,159
Total Expected Plan Costs	1,159		1,159
Other costs
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	672		672
Total Expected Plan Costs	749		749
Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring costs	86	11,578	261	11,578
Operating expenses \| Severance and related employee benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	10,107	0	10,107
Operating expenses \| Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	1,358	0	1,358
Operating expenses \| Other costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 86	$ 113	$ 261	$ 113