Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Other Commitments [Line Items]
Severance payment under agreement description	Certain of the agreements also provide for a severance payment of one to three times annual salary and one half to three times average annual bonus if such an agreement is terminated without good cause by the employer or for good reason by the employee.
Employees under contract terminated by employer without good cause or change in control	$ 36.1
Employees under contract terminated by employer without good cause or in absence of change in control	$ 16.0
Minimum [Member]
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	6 months
Maximum [Member]
Other Commitments [Line Items]
Period for providing minimum compensation salary and continuation of certain benefits to executives under employment agreements	3 years