Earnings per Share: (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Earnings per Share:                      
Income from continuing operations $ 5,848 $ (2,697) $ 10,498 $ 12,888 $ 18,554 $ 10,040 $ 8,830 $ 7,878 $ 26,537 $ 45,302 $ 19,924
Less net income allocated to participating unvested share awards                 (79) (338) (279)
Income from continuing operations attributable to common shares                 $ 26,458 $ 44,964 $ 19,645
Weighted average common shares outstanding - basic (in shares)                 27,516 27,226 22,572
Dilutive stock options, RSUs and warrants                 244 344 519
Weighted average common shares outstanding - diluted (in shares)                 27,760 27,570 23,091
Basic net income (loss) per common share:                      
Continuing (in dollars per share) $ 0.21 $ (0.10) $ 0.38 $ 0.46 $ 0.66 $ 0.35 $ 0.31 $ 0.32 $ 0.96 $ 1.65 $ 0.87
Discontinued (in dollars per share) $ (0.05)   $ (0.01) $ (0.01) $ (0.14)   $ 0.01 $ 0.01 $ (0.07) $ (0.13) $ 0.03
Total (in dollars per share) $ 0.16 $ (0.10) $ 0.37 $ 0.45 $ 0.52 $ 0.35 $ 0.32 $ 0.33 $ 0.89 $ 1.52 $ 0.90
Diluted net income (loss) per common share:                      
Continuing (in dollars per share) $ 0.21 $ (0.10) $ 0.38 $ 0.46 $ 0.65 $ 0.35 $ 0.31 $ 0.31 $ 0.95 $ 1.63 $ 0.85
Discontinued (in dollars per share) $ (0.05)   $ (0.01) $ (0.01) $ (0.14) $ (0.01) $ 0.01 $ 0.01 $ (0.07) $ (0.13) $ 0.03
Total (in dollars per share) $ 0.16 $ (0.10) $ 0.37 $ 0.45 $ 0.51 $ 0.34 $ 0.32 $ 0.32 $ 0.88 $ 1.50 $ 0.88
Antidilutive securities not included:                      
Stock options, warrants and RSUs                 1,818 556 819