Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Commitments [Line Items]
Operating lease, rental expense	$ 7,700,000	$ 6,700,000	$ 5,600,000
Purchase commitment, total	14,600,000
Commitments to be paid in 2017	7,400,000
Commitments to be paid in 2018	4,200,000
Commitments to be paid in 2019	2,600,000
Commitments to be paid in 2020	400,000
Commitments to be paid in 2021	0
Letter of credit outstanding, for workers compensation	3,100,000
Letter of credit outstanding, for facility lease deposit	400,000
Employees under contract terminated by employer without good cause or change in control	43,600,000
Employees under contract terminated by employer without good cause or in absence of change in control	$ 17,600,000
Minimum
Other Commitments [Line Items]
Tenure of expiration of lease	30 days
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	6 months
Severance payment as a percentage of annual salary	100.00%
Severance payment as a percentage of annual bonus	50.00%
Maximum
Other Commitments [Line Items]
Tenure of expiration of lease	90 days
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	3 years
Severance payment as a percentage of annual salary	300.00%
Severance payment as a percentage of annual bonus	300.00%