Other Income (Expense) - Other income (expense) summary (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income and Expenses [Abstract]
Interest and dividend income		$ 5,900	$ 6,258	$ 1,171
Accretion income		2,566	1,455	0
Realized gains (losses) on the sale of investments		5,311	(833)	93
Other-than-temporary impairment losses	$ (1,300)	0	(1,295)	0
Total net investment income from available-for-sale securities		13,777	5,585	1,264
Interest income from investments in special purpose entities		8,217	6,116	0
Interest accrued on notes receivable and other interest		694	990	234
Total investment income, net		22,688	12,691	1,498
Interest expense and amortization of discount and issuance costs for Senior Notes issued by special purpose entity		(8,755)	(6,584)	0
Interest expense		(2,674)	(2,024)	(2,040)
Total interest expense		(11,429)	(8,608)	(2,040)
Fees and expenses for the SEC investigation		(8,161)	0	0
Accretion income from retained interest investments		913	889	793
Hunting lease income		738	938	1,850
Litigation and insurance proceeds received		0	1,814	560
Other income, net		223	847	1,007
Other, net		(6,287)	4,488	4,210
Total other income		$ 4,972	$ 8,571	$ 3,668