Assets Held-for-Sale and Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets held-for-sale
Assets held for sale	$ 134,709us-gaap_AssetsHeldForSaleCurrent	$ 146,467us-gaap_AssetsHeldForSaleCurrent
Oil and Gas
Assets held-for-sale
Assets held for sale	$ 134,700	$ 146,500

Current assets (normally turning over within one year or one business cycle if longer) that are held for sale apart from normal operations and anticipated to be sold within one year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759

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