Noncontrolling Interests (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components on noncontrolling interests
Net income attributable to nonredeemable noncontrolling interests	$ 3,525	$ 2,364	$ 2,426
Net income (loss) attributable to redeemable noncontrolling interests	1,433	176	(174)
Net income attributable to noncontrolling interests	$ 4,958	$ 2,540	$ 2,252