Investment Securities (Components of Cash Equivalents and Marketable Securities) (Details) (USD $) In Thousands, unless otherwise specified					12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Money market funds [Member]	Dec. 31, 2013 Money market funds [Member]	Dec. 31, 2013 Corporate bonds (unamortized cost) [Member]	Dec. 31, 2013 U.S. Treasury obligations (unamortized cost) [Member]	Sep. 30, 2014 Common shares of CO2 Solution [Member]	Dec. 31, 2013 Common shares of CO2 Solution [Member]
Cash Equivalents and Marketable Securities [Line Items]
Adjusted Cost	$ 15,163	$ 19,654	$ 14,600	$ 16,089	$ 1,002	$ 2,000	$ 563	$ 563
Gross Unrealized Gains	468	235	0	0	3	0	468	232
Gross Unrealized Losses	0	0	0	0	0	0	0	0
Estimated Fair Value	$ 15,631	$ 19,889	$ 14,600	$ 16,089	$ 1,005	$ 2,000	$ 1,031	$ 795
Average Contractual Maturities (in days)					140 days	59 days