Allowance for Doubtful Accounts - Summary of Activity in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Receivables [Abstract]
Balance at the beginning of period	$ 786	$ 1,338
Bad debt expense (recovery)	95	(268)
Write-offs	(67)	(11)
Balance at the end of period	$ 814	$ 1,059

Amount of direct write-downs of accounts receivable charged against the allowance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 310
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68075217&loc=SL9156395-115594

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration