Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Statement of Stockholders' Equity [Abstract]
Redemption value change, Redeemable Noncontrolling Interests	$ 962	$ 1,555
Mandatorily redeemable noncontrolling interests	$ 1,555	$ 450

Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

No definition available.

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