Convertible Notes, Long-Term Debt and Credit Facility (Convertible Notes and Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Convertible notes:
Convertible senior notes, net of discount	$ 0	$ 5,133
Long-term debt:
Term loan	62,105
Capital lease obligations	0	1,784
Debt and Capital Lease Obligations	62,105	26,784
Less amount reported as current	(26,415)	(4,329)
Long-term debt, less current portion	35,690	22,455
Convertible senior notes [Member]
Convertible notes:
Less discount on notes	0	(55)
Convertible senior notes, net of discount	0	5,133
Term loan [Member]
Long-term debt:
Term loan	45,833	25,000
Convertible senior unsecured notes (2008 Notes) [Member] | Convertible senior notes [Member]
Convertible notes:
Long-term debt, gross	0	5,188
Revolving Credit Facility [Member]
Long-term debt:
Amount borrowed	$ 16,272	$ 0