Other Income, net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of other income, net
Other income, net	$ 10,109	$ 8,103	$ 4,072
Agency and commitment fees
Components of other income, net
Other income, net	(1,473)	(1,192)	(1,656)
Interest income
Components of other income, net
Other income, net	11,512	10,245	5,046
Other
Components of other income, net
Other income, net	$ 70	$ (950)	$ 682