Concentration of Credit Risk (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) financial_institution	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Risks and Uncertainties [Abstract]
Number of financial institutions with cash deposits held (more than 1) | financial_institution	1
Cash and cash equivalents held at two financial institutions	$ 76,661
Cash and cash equivalents	$ 87,757	$ 76,217	$ 110,822	$ 93,452