Consolidated Income Statements (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Consolidated Income Statements [Abstract]
Increase in redeemable noncontrolling interest to redemption value	$ 8,237

Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.

No definition available.

Name:	us-gaap_MinorityInterestChangeInRedemptionValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration