Summary of Significant Accounting Policies - Goodwill and Other Intangibles (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017
Impairment to goodwill or intangible assets		$ 0
Business Consideration	$ 91,400,000
Other liabilities
Contingent consideration	$ 685,000
Maximum
Usefule life	9 years
Minimum
Usefule life	5 years
Customer Relationships
Other intangibles	$ 1,400,000