Accounting Policies Recently Adopted and Pending Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Total outstanding operating lease obligation		$ 58.0
Percentage of total outstanding operating lease obligation of total assets		0.40%
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Percentage of revenues earned	23.00%