Changes in the Carrying Value of Goodwill (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill Roll Forward
Net carrying value at beginning of period	$ 106,100	$ 106,100	$ 146,259
Acquisitions	23,606	0	0
Impairment charge	0	0	(40,159)
Net carrying value at end of period	$ 129,706	$ 106,100	$ 106,100