Summary of Significant Accounting Policies (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income (loss) - numerator
Net (loss) income	$ (21,188)	$ (9,197)	$ (6,676)	$ 3,801	$ 3,941	$ 6,194	$ 7,152	$ (27,596)	$ (33,261)	$ (10,309)	$ 6,377
Less dividends to Class B shareholders - distributed earnings									(28)	(275)	(275)
Undistributed (loss) earnings									$ (33,289)	$ (10,584)	$ 6,102
Weighted average common shares outstanding - denominator
Weighted average common shares outstanding for basic earnings (loss) per share									53,957	42,718	41,038
Diluted									53,957	42,718	41,134
Class A [Member]
Weighted average common shares outstanding - denominator
Weighted average common shares outstanding for basic earnings (loss) per share									53,852	41,687	40,007
Dilutive effect of options											96
Diluted									53,852	41,687	40,103
Basic
Distributed earnings
Undistributed (loss) earnings									$ (0.62)	$ (0.25)	$ 0.15
Total	$ (0.38)	$ (0.17)	$ (0.12)	$ 0.08	$ 0.09	$ 0.14	$ 0.17	$ (0.65)	$ (0.62)	$ (0.25)	$ 0.15
Diluted
Distributed earnings
Undistributed (loss) earnings									$ (0.62)	$ (0.25)	$ 0.15
Total	$ (0.38)	$ (0.17)	$ (0.12)	$ 0.08	$ 0.09	$ 0.14	$ 0.17	$ (0.65)	$ (0.62)	$ (0.25)	$ 0.15
Class B [Member]
Weighted average common shares outstanding - denominator
Weighted average common shares outstanding for basic earnings (loss) per share									105	1,031	1,031
Diluted									105	1,031	1,031
Basic
Distributed earnings									$ 0.27	$ 0.27	$ 0.27
Undistributed (loss) earnings									$ (0.62)	$ (0.25)	$ 0.15
Total	$ 0.00	$ 0.00	$ 0.00	$ 0.15	$ 0.16	$ 0.21	$ 0.23	$ (0.58)	$ (0.35)	$ 0.02	$ 0.42
Diluted
Distributed earnings									$ 0.27	$ 0.27	$ 0.27
Undistributed (loss) earnings									$ (0.62)	$ (0.25)	$ 0.15
Total	$ 0.00	$ 0.00	$ 0.00	$ 0.15	$ 0.16	$ 0.21	$ 0.23	$ (0.58)	$ (0.35)	$ 0.02	$ 0.42