Investments - Schedule of Fair Value of Financial Instruments with Unobservable Inputs (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
June 30, 2015	$ 399,290
Other Long-Term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
June 30, 2015	3,131
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
June 30, 2015	2,000
Level 3 | Other Long-Term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
December 31, 2014	1,971
Transfers in	0
Partnership income	43
Return of capital	(44)
Unrealized gains in accumulated other comprehensive income	30
June 30, 2015	$ 2,000