Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]
Operating lease, rent expense	$ 3.4	$ 3.4	$ 2.7
Minimum [Member]
Operating Leased Assets [Line Items]
Operating lease period	1 year
Renewal option period	1 year
Maximum [Member]
Operating Leased Assets [Line Items]
Operating lease period	30 years
Renewal option period	59 years