Guarantees - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ in Thousands	Total
Guarantor Obligations [Line Items]
Guarantor obligations, standby letters of credit	$ 189,900
Liability related to standby letters of credit	726
Secured
Guarantor Obligations [Line Items]
Guarantor obligations, standby letters of credit	$ 132,000
Percent of secured letters of credit	69.50%