Organization and Basis of Presentation - Summary of Financial Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, carrying value	$ 133,058	$ 117,240
Available-for-sale securities and held-to-maturity securities, amortized cost		106,955
Available-for-sale securities and held-to-maturity securities, gross unrealized gain		5,285
Available-for-sale securities and held-to-maturity securities, carrying value		112,240
Other investments, amortized cost		5,000
Other investments, gross unrealized gain		0
Other investments, carrying value		5,000
Marketable securities and other investments, amortized cost	128,299	111,955
Marketable securities and other investments, gross unrealized gain	4,759	5,285
Marketable securities and other investments	133,058	117,240
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	11,633	9,435
Available-for-sale securities, gross unrealized gain	144	145
Available-for-sale securities, carrying value	11,777	9,580
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	5,020	3,769
Available-for-sale securities, gross unrealized gain	6	3
Available-for-sale securities, carrying value	5,026	3,772
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	34,653	25,755
Available-for-sale securities, gross unrealized gain	4,609	5,137
Available-for-sale securities, carrying value	39,262	30,892
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, amortized cost	76,993	67,996
Held-to-maturity securities, gross unrealized gain	0	0
Held-to-maturity securities, carrying value	$ 76,993	$ 67,996