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
Beginning Balance (in shares) at Dec. 31, 2015			8,398,944	0				1,214,144
Beginning Balance at Dec. 31, 2015	$ 509,457		$ 96	$ 0	$ 1,140,875	$ (472,614)	$ (1,034)	$ (157,699)	$ 509,624		$ (167)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	36,076					36,076			36,076
Net unrealized gain (loss) on securities available-for-sale	230						230		230
Foreign currency translation adjustments	569						569		569
Activity of noncontrolling interests, net						(167)			(167)		167
Cash dividends declared	(11,003)				(11,003)				(11,003)
Repurchases of common shares (in shares)			(844,671)					(288,155)
Repurchases of common shares	(72,216)		$ (6)		(47,207)			$ (25,003)	(72,216)
Issuance of common shares related to employee stock transactions (in shares)			55,480
Issuance of common shares related to employee stock transactions	992		$ 1		991				992
Taxes paid on stock-based compensation	(1,518)				(1,518)				(1,518)
Stock-based compensation	8,815				8,815				8,815
Tax deficiencies from stock-based compensation	(1,603)				(1,603)				(1,603)
Ending Balance (in shares) at Sep. 30, 2016			7,609,753	0				1,502,299
Ending Balance at Sep. 30, 2016	469,799		$ 91	$ 0	1,089,350	(436,705)	(235)	$ (182,702)	469,799		0
Beginning Balance at Dec. 31, 2015	73,864
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	770
Activity of noncontrolling interests, net	(44,333)
Ending Balance at Sep. 30, 2016	30,301
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for adoption of ASU 2016-09	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)	32,587					31,514			31,514		1,073
Net unrealized gain (loss) on securities available-for-sale	172						172		172
Foreign currency translation adjustments	12						12		12
Activity of noncontrolling interests, net	15,414										15,414
Cash dividends declared	$ (10,103)				(10,103)				(10,103)
Repurchases of common shares (in shares)	(66,244)		(66,244)					(66,244)
Repurchases of common shares	$ (7,502)							$ (7,502)	(7,502)
Issuance of common shares related to employee stock transactions (in shares)			75,077
Issuance of common shares related to employee stock transactions	836		$ 1		835				836
Taxes paid on stock-based compensation	(3,441)				(3,441)				(3,441)
Stock-based compensation	14,317				14,317				14,317
Issuance of stock, net of offering costs (in shares)			1,046,500	1,150,000
Issuance of stock, net of offering costs	109,328	$ 110,843	$ 11	$ 110,843	109,317				109,328	$ 110,843
Dividends	(6,253)				(6,253)				(6,253)
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
Ending Balance (in shares) at Sep. 30, 2017			7,158,015	1,150,000				3,296,289
Ending Balance at Sep. 30, 2017	600,674		$ 105	$ 110,843	$ 1,216,741	$ (391,714)	$ (40)	$ (351,748)	$ 584,187		$ 16,487
Beginning Balance at Dec. 31, 2016	37,266
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	1,709
Activity of noncontrolling interests, net	28,252
Ending Balance at Sep. 30, 2017	$ 67,227