Condensed Consolidated Statements of Changes in Equity - 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	20,451					20,451			20,451
Net unrealized gain (loss) on securities available-for-sale	281						281		281
Foreign currency translation adjustments	569						569		569
Cash dividends declared	(7,452)				(7,452)				(7,452)
Repurchases of common shares	(62,139)		$ (6)		(47,133)			$ (15,000)	(62,139)
Repurchases of common shares (in shares)			(732,713)					(176,204)
Issuance of common shares related to employee stock transactions (in shares)			51,832
Issuance of common shares related to employee stock transactions	964		$ 1		963				964
Taxes paid on stock-based compensation	(1,332)				(1,332)				(1,332)
Stock-based compensation	6,620				6,620				6,620
Tax deficiencies from stock-based compensation	(1,313)				(1,313)				(1,313)
Ending Balance (in shares) at Jun. 30, 2016			7,718,063	0				1,390,348
Ending Balance at Jun. 30, 2016	466,106		$ 91	$ 0	1,091,228	(452,163)	(184)	$ (172,699)	466,273		(167)
Beginning Balance at Dec. 31, 2015	73,864
Increase (Decrease) in Redeemable Non-controlling Interests [Roll Forward]
Net income (loss)	119
Activity of noncontrolling interests, net	(46,838)
Ending Balance at Jun. 30, 2016	27,145
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]
Cumulative effect adjustment for adoption of ASU 2016-09	1,051					1,051			1,051
Net income	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
Dividends	(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	(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