Condensed Consolidated Statements of Cash Flows (Parenthetical) - shares shares in Thousands	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Condensed Consolidated Statements of Cash Flows
Issuance of shares of common stock to fund the Company's 401(k) matching contribution	158,717	341,507

Number of shares issued pursuant to the terms of a deferred compensation arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Name:	us-gaap_DeferredCompensationArrangementWithIndividualSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration