Net Income per Share of Common Stock (Narrative) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Numerator for earnings per share:
Net income that is available to common shareholders	$ 6,966	$ 23,641	$ 70,086
Denominator for basic earnings per share:
Weighted average shares outstanding	20,875,959	20,169,638	17,668,214
Effect of stock options and restricted stock units	439,252	492,557	501,395
Effect of warrants	0	145,882	1,787,472
Total effect of dilutive securities	439,252	638,439	2,288,867
Denominator for diluted earnings per share:
Adjusted weighted average shares and assumed conversions	21,315,211	20,808,077	19,957,081
Basic earnings per share	$ 0.33	$ 1.17	$ 3.97
Diluted earnings per share	$ 0.33	$ 1.14	$ 3.51