Goodwill and Acquired Intangible Assets - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	$ 1,587,000
Goodwill	25,211,000	$ 25,309,000
Business Combination, Bargain Purchase, Gain Recognized, Amount	416,000	$ 0	$ 0
Finite-Lived Intangible Assets, Amortization Expense, Year Four	$ 1,482,000