Noncontrolling Interests (Reconciliation of Net Income Attributable to Noncontrolling Interests) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components on noncontrolling interests
Net income attributable to nonredeemable noncontrolling interests	$ 4,193	$ 3,525	$ 2,364
Net income (loss) attributable to redeemable noncontrolling interests	(2,002)	1,433	176
Net income attributable to noncontrolling interests	$ 2,191	$ 4,958	$ 2,540