Other Income (Expense) - Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Investment income, net
Interest and dividend income	$ 4,445	$ 1,528	$ 13,016	$ 1,969
Accretion income	375	960	1,696	2,002
Realized (loss) gain on the sale of investments	(104)	40	10,757	40
Other-than-temporary impairment loss	(403)	0	(769)	0
Total net investment income from available-for-sale securities	4,313	2,528	24,700	4,011
Interest income from investments in SPEs	2,050	2,051	6,151	6,151
Interest accrued on notes receivable and other interest	89	110	259	216
Total investment income, net	6,452	4,689	31,110	10,378
Interest expense
Interest expense and amortization of discount and issuance costs for Senior Notes issued by SPE	(2,195)	(2,259)	(6,582)	(6,640)
Other interest expense	(843)	(816)	(2,535)	(2,615)
Total interest expense	(3,038)	(3,075)	(9,117)	(9,255)
Claim settlement	0	0	0	12,548
Other income, net
Accretion income from retained interest investments	279	249	813	733
Hunting lease income	145	138	424	415
Miscellaneous income, net	493	48	4,323	339
Other income, net	917	435	5,560	1,487
Total other income, net	$ 4,331	$ 2,049	$ 27,553	$ 15,158