Organization and Basis of Presentation - Summary of Financial Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, carrying value	$ 138,597	$ 137,485
Marketable securities and other investments, amortized cost	131,130	130,335
Marketable securities and other investments, gross unrealized gain	7,467	7,150
Marketable securities	138,597	137,485
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	9,603	11,618
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	154	68
Available-for-sale securities, carrying value	9,757	11,686
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	5,019	3,675
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	2	(9)
Available-for-sale securities, carrying value	5,021	3,666
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, amortized cost	32,576	34,655
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	7,311	7,091
Available-for-sale securities, carrying value	39,887	41,746
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity Securities, amortized cost	83,932	80,387
Held-to-maturity securities, gross unrealized gain	0	0
Held-to-maturity securities, carrying value	$ 83,932	$ 80,387