Reorganization items, net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Reorganization items, net	$ (301)	$ (2,828)
Payments for reorganization items	$ 200	$ 3,700

Amount of gain (loss) on settlement of other claims for entities not in bankruptcy, reported as a reorganization item.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64805424&loc=d3e55730-112764

Name:	us-gaap_NondebtorReorganizationItemsNetGainLossOnSettlementOfOtherClaims1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration