Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements of Equity [Abstract]
Redemption value change, Redeemable Noncontrolling Interests	$ 1,555	$ 757	$ 632
Mandatorily redeemable noncontrolling interests	$ 450	$ 419	$ 485

The portion of net income or loss for the period attributable to redeemable noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent. This element should be used for redeemable noncontrolling interests that are classified within temporary equity.

No definition available.

Name:	us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration