Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Employee	Dec. 31, 2012	Dec. 31, 2011
Leases And Employment Agreements Disclosure [Line Items]
Operating lease expense	$ 2.7	$ 2.5	$ 2.3
Number Of Senior Executives	1
Senior Executives
Leases And Employment Agreements Disclosure [Line Items]
Employment agreement term	3 years
Vice Chairman Of Board Of Directors
Leases And Employment Agreements Disclosure [Line Items]
Employment agreement term	2 years
Minimum
Leases And Employment Agreements Disclosure [Line Items]
Operating lease, initial term	1 year
Maximum
Leases And Employment Agreements Disclosure [Line Items]
Operating lease, initial term	25 years