CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2010	$ 162,413	$ 360	$ 297,714	$ (141,137)	$ 5,476
Balance (in shares) at Dec. 31, 2010		36,019,864
Comprehensive income:
Net income (loss)	72,174			72,174
Unrealized gain on investments in available for sale securities, net of tax	24				24
Realized gain (loss) on investments in available for sale securities reclassified and included in net income, net of tax	(2,460)				(2,460)
Equity in unrealized gain (loss) of an investee, net of tax	76				76
Comprehensive (loss) income	69,814			72,174	(2,360)
Grants under share award plan and share based compensation	1,174	4	1,170
Grants under share award plan and share based compensation (in shares)		379,448
Issuance of stock, pursuant to equity offering	53,953	115	53,838
Issuance of stock, pursuant to equity offering (in shares)		11,500,000
Balance at Dec. 31, 2011	287,354	479	352,722	(68,963)	3,116
Balance (in shares) at Dec. 31, 2011		47,899,312
Comprehensive income:
Net income (loss)	22,307			22,307
Unrealized gain on investments in available for sale securities, net of tax	214				214
Realized gain (loss) on investments in available for sale securities reclassified and included in net income, net of tax	11				11
Equity in unrealized gain (loss) of an investee, net of tax	22				22
Comprehensive (loss) income	22,554			22,307	247
Grants under share award plan and share based compensation	1,445	3	1,442
Grants under share award plan and share based compensation (in shares)		347,050
Repurchases under share award plan (in shares)		(12,340)
Balance at Dec. 31, 2012	311,353	482	354,164	(46,656)	3,363
Balance (in shares) at Dec. 31, 2012	48,234,022	48,234,022
Comprehensive income:
Net income (loss)	(2,340)			(2,340)
Unrealized gain on investments in available for sale securities, net of tax	4				4
Realized gain (loss) on investments in available for sale securities reclassified and included in net income, net of tax	2				2
Equity in unrealized gain (loss) of an investee, net of tax	(51)				(51)
Comprehensive (loss) income	(2,385)			(2,340)	(45)
Grants under share award plan and share based compensation	1,410	4	1,406
Grants under share award plan and share based compensation (in shares)		385,400
Repurchases under share award plan (in shares)		(5,980)
Balance at Dec. 31, 2013	$ 310,378	$ 486	$ 355,570	$ (48,996)	$ 3,318
Balance (in shares) at Dec. 31, 2013	48,613,442	48,613,442