Significant Accounting Policies - Additional Information (Details)	Dec. 31, 2016 USD ($)
Income Tax [Line Items]
Income tax liabilities	$ 8,424,000
2015
Income Tax [Line Items]
Income tax liabilities	8,400,000
2014
Income Tax [Line Items]
Income tax liabilities	0
2016
Income Tax [Line Items]
Income tax liabilities	$ 0