Consolidated Statements of Shareholders' Equity and Comprehensive Income (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common [Member]	Treasury [Member]	Additional Paid In Capital [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Restricted Stock [Member]	Restricted Stock [Member] Additional Paid In Capital [Member]	Stock Options [Member]	Stock Options [Member] Additional Paid In Capital [Member]
Balance, value at Dec. 31, 2008	$ 414,118	$ 5,000	$ 0	$ 301,923	$ 108,440	$ (1,245)
Balance, shares at Dec. 31, 2008		49,998,000	0
Comprehensive income (loss):
Net income (loss)	(23,215)				(23,215)
Impact of impairment of investments charge	0
Unrealized loss on securities	(448)					(448)
Comprehensive income (loss)	(23,663)
Sale of common stock, net of offering costs, shares		3,820,000
Sale of common stock, net of offering costs, value	24,043	382		23,661
Purchase of treasury stock, shares			(5,000)
Purchase of treasury stock, value	(31)		(31)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation							(235)	(235)
Issuance of restricted stock, shares		308,000
Issuance of restricted stock, value	0	31		(31)
Stock-based compensation expense	7,216			7,216
Balance, value at Dec. 31, 2009	421,448	5,413	(31)	332,534	85,225	(1,693)
Balance, shares at Dec. 31, 2009		54,126,000	(5,000)
Comprehensive income (loss):
Net income (loss)	(33,261)				(33,261)
Impact of impairment of investments charge	1,693					1,693
Unrealized loss on securities	0
Comprehensive income (loss)	(31,568)
Exercise of options and related income tax effect of $16, shares		63,000
Exercise of options and related income tax effect of $16, value	254	6		248
Purchase of treasury stock, shares			(20,000)
Purchase of treasury stock, value	(130)		(130)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation							(120)	(120)	(226)	(226)
Issuance of restricted stock, shares		64,000
Issuance of restricted stock, value	0	6		(6)
Stock-based compensation expense	6,675			6,675
Balance, value at Dec. 31, 2010	396,333	5,425	(161)	339,105	51,964	0
Balance, shares at Dec. 31, 2010	54,228,170	54,253,000	(25,000)
Comprehensive income (loss):
Net income (loss)	11,177				11,177
Impact of impairment of investments charge	0
Unrealized loss on securities	0
Comprehensive income (loss)	11,177
Sale of common stock, net of offering costs, shares		6,900,000
Sale of common stock, net of offering costs, value	94,343	690		93,653
Exercise of options and related income tax effect of $16, shares		517,000
Exercise of options and related income tax effect of $16, value	2,884	52		2,832
Purchase of treasury stock, shares			(70,000)
Purchase of treasury stock, value	(743)		(743)
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation									(254)	(254)
Issuance of restricted stock, shares		207,000
Issuance of restricted stock, value	0	21		(21)
Stock-based compensation expense	6,705			6,705
Balance, value at Dec. 31, 2011	$ 510,445	$ 6,188	$ (904)	$ 442,020	$ 63,141	$ 0
Balance, shares at Dec. 31, 2011	61,782,180	61,877,000	(95,000)