Summary of Significant Accounting Policies - Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Beginning balance - accumulated other comprehensive income	$ 8,820
Unrealized loss on investment in Global	(9,209)	(4,626)
Foreign Currency Translation Adjustments	(548)	160
Other Comprehensive Income (Loss)	(8,820)	(4,466)
Ending balance - accumulated other comprehensive income		8,820
Current Period Unrealized Loss
Unrealized loss on investment in Global	(9,209)
Foreign Currency Translation Adjustments	(548)
Other Comprehensive Income (Loss)	(9,757)
Impairment (Gain) Loss Recognized on Investment in Global
Unrealized loss on investment in Global	1,604
Foreign Currency Translation Adjustments	(667)
Other Comprehensive Income (Loss)	937
Accumulated Other Comprehensive Income
Beginning balance - unrealized loss on investments	7,605
Beginning balance - unrealized foreign currency translation adjustments	1,215
Beginning balance - accumulated other comprehensive income	8,820
Unrealized loss on investment in Global	(9,209)	(4,626)
Foreign Currency Translation Adjustments	(548)	160
Ending balance - unrealized loss on investments	0	7,605
Ending balance - unrealized foreign currency translation adjustments	0	1,215
Ending balance - accumulated other comprehensive income	$ 0	$ 8,820