CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net income allocable to common shareholders	$ 61,002	$ 19,402
Net loss allocable to noncontrolling interests	0	(45,339)
Net income (loss)	61,002	(25,937)
Bond related changes:
Net unrealized gains	5,620	4,216
Reclassification of fair value gains on sold or redeemed bonds into the Consolidated Statements of Operations	(21,875)	(620)
Reclassification of credit-related losses (gains) to the Consolidated Statements of Operations related to bond investments assessed as other-than-temporary-impairment ("OTTI")	6	(135)
Reinstatement of fair value gains related to bond investments due to deconsolidation of consolidated property partnerships	9,415	0
Net change in other comprehensive income due to bonds	(6,834)	3,461
Foreign currency translation adjustment	3,378	(126)
Other comprehensive (loss) income allocable to common shareholders	(3,456)	3,335
Other comprehensive loss allocable to noncontrolling interests:
Unrealized net losses		(26)
Other comprehensive loss allocable to noncontrolling interests		(26)
Comprehensive income to common shareholders	57,546	22,737
Comprehensive loss to noncontrolling interests	0	(45,365)
Comprehensive income (loss)	$ 57,546	$ (22,628)