The cumulative amount of the reporting entity's undistributed earnings or deficit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30)(a)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(a)(4))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - CUMULATIVE EFFECT ADJUSTMENTS FOR THE ADOPTION OF TOPIC 606 AND ASU 2016-01 AND ASU 2018-03 (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Interest and other receivables	$ 778	$ 640	$ 436
Other assets	851	1,189
Stockholders' equity:
Accumulated deficit	$ (1,004,164)	(984,447)	$ (985,840)
ASU 2014-09 \| Adjustments Due to Topic 606
ASSETS
Interest and other receivables		204
Stockholders' equity:
Accumulated deficit		204
Adjustments Due to ASU 2016-01 and ASU 2018-03
ASSETS
Other assets		1,189
Stockholders' equity:
Accumulated deficit		$ 1,189