Basis of Presentation and Significant Accounting Policies - Marketable Equity Securities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net proceeds from sale of marketable securities	$ 0	$ 230	$ 2,467