Equity Method Investments - Investment in Unconsolidated Affiliates by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments in and Advances to Affiliates [Line Items]
Investments in unconsolidated affiliates	$ 92,196	$ 109,248	$ 144,475
Operating Segments \| Global Power
Investments in and Advances to Affiliates [Line Items]
Investments in unconsolidated affiliates	75,946	93,389	99,013
Operating Segments \| Global Services
Investments in and Advances to Affiliates [Line Items]
Investments in unconsolidated affiliates	$ 16,250	$ 15,859	$ 45,462

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant