Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Series D convertible preferred stock	Common Stock	Preferred Stock Series D convertible preferred stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total Attributed To Stockholders	Total Attributed To Stockholders Series D convertible preferred stock	Non- controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for adoption of ASU	$ 1,051					$ 1,051			$ 1,051
Beginning Balance (in shares) at Dec. 31, 2016			5,889,013	0				3,230,045
Beginning Balance at Dec. 31, 2016	321,673		$ 91	$ 0	$ 1,090,331	(424,279)	$ (224)	$ (344,246)	321,673		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	12,722					12,722			12,722
Net unrealized gain (loss) on securities available-for-sale	134						134		134
Foreign currency translation adjustments	2						2		2
Activity of noncontrolling interests, net	15,731										15,731
Issuance of stock, net of offering costs (in shares)			1,046,500	1,150,000
Issuance of stock, net of offering costs	109,320	$ 110,837	$ 10	$ 110,837	109,310				109,320	$ 110,837
Cash dividends declared, preferred	(4,168)				(4,168)				(4,168)
Issuance of common stock for acquisition of business (in shares)			213,669
Issuance of common stock for acquisition of business	21,740		$ 2		21,738				21,740
Cash dividends declared, common	(6,670)				(6,670)				(6,670)
Issuance of common shares related to employee stock transactions (in shares)			68,726
Issuance of common shares related to employee stock transactions	817		$ 1		816				817
Taxes paid on stock-based compensation	(3,029)				(3,029)				(3,029)
Stock-based compensation	9,173				9,173				9,173
Ending Balance (in shares) at Jun. 30, 2017			7,217,908	1,150,000				3,230,045
Ending Balance at Jun. 30, 2017	589,333		$ 104	$ 110,837	1,217,501	(410,506)	(88)	$ (344,246)	573,602		15,731
Beginning Balance at Dec. 31, 2016	37,266
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	1,051
Activity of noncontrolling interests, net	19,019
Ending Balance at Jun. 30, 2017	57,336
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for adoption of ASU						(178)	178
Beginning Balance (in shares) at Dec. 31, 2017			7,159,645	1,150,000				3,296,289
Beginning Balance at Dec. 31, 2017	605,224		$ 105	$ 110,843	1,216,173	(386,216)	(600)	$ (351,748)	588,557		16,667
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	47,136					46,370			46,370		766
Net unrealized gain (loss) on securities available-for-sale	(192)						(192)		(192)
Foreign currency translation adjustments	(8)						(8)		(8)
Activity of noncontrolling interests, net	(1,462)										(1,462)
Cash dividends declared, preferred	(4,168)				(4,168)				(4,168)
Cash dividends declared, common	$ (6,877)				(6,877)				(6,877)
Repurchases of common shares (in shares)	(60,622)		(60,622)					(60,622)
Repurchases of common shares	$ (7,500)							$ (7,500)	(7,500)
Issuance of common shares related to employee stock transactions (in shares)			67,116
Issuance of common shares related to employee stock transactions	1,378				1,378				1,378
Taxes paid on stock-based compensation	(5,238)				(5,238)				(5,238)
Stock-based compensation	12,073				12,073				12,073
Ending Balance (in shares) at Jun. 30, 2018			7,166,139	1,150,000				3,356,911
Ending Balance at Jun. 30, 2018	640,366		$ 105	$ 110,843	$ 1,213,341	$ (340,024)	$ (622)	$ (359,248)	$ 624,395		$ 15,971
Beginning Balance at Dec. 31, 2017	4,178
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	(80)
Activity of noncontrolling interests, net	(678)
Ending Balance at Jun. 30, 2018	$ 3,420