Summary of Significant Accounting Policies Restricted Cash (Tables)

9 Months Ended

Sep. 30, 2018

Cash and Cash Equivalents [Abstract]

Schedule of Cash, Cash Equivalents, and Restricted Cash [Table Text Block]

The following table provides a reconciliation of the cash and cash equivalents between the Condensed Consolidated Balance Sheets and the Condensed Consolidated Statement of Cash Flows as of September 30, 2018 and 2017, and December 31, 2017 and 2016:

	September 30,				December 31,
	2018		2017		2017		2016
Cash and cash equivalents	$	164,216	$	105,718	$	207,534	$	165,011
Restricted cash included within other current assets	598		265		526		139
Restricted cash included within other non-current assets	—		355		102		419
Total cash, cash equivalents and restricted cash	$	164,814	$	106,338	$	208,162	$	165,569