Arrangements with Variable Interest Entities and Joint Ventures - Noncontrolling Interest (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance, January 1	$ 95,910	$ 104,788
Accretion of redeemable non-controlling interests, before tax	28	(7,844)
Purchase of membership units of non-controlling interest	(5,250)	0
Loans made to joint venture partner	(8,255)	0
Optional distribution made to joint venture partner	(16,243)	0
Other	(1,673)	(1,034)
Ending balance, December 31	$ 64,517	$ 95,910