Non-controlling Interest (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Non-controlling Interest [Abstract]
Non-controlling interest in joint ventures	$ 13,808	$ 13,704

Carrying amount of the equity interests owned by noncontrolling shareholders, partners, or other equity holders in joint ventures included in the entity's consolidated financial statements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4568740-111683

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