Marketable Securities and Fair Value Measurements Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Maturity Period Used To Classify Investments	8 months	9 months
Maximum
Schedule of Available-for-sale Securities [Line Items]
Maturity Period Used To Classify Investments	27 months
Other Assets | Fair Value, Inputs, Level 3
Schedule of Available-for-sale Securities [Line Items]
Notes Receivable, Fair Value Disclosure	$ 2.0