Employee Pension Benefits - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Service cost included in net periodic pension benefit			$ 0
ESI Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plans	0	0	0	0
ESI Excess Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plans	$ 0	$ 0	$ 0	$ 0