Employee Benefits (Details 2) (Restricted Stock, USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Restricted Stock
     
Summary of restricted stock activity [Rollforward]      
Number of shares, Nonvested, Beginning (in shares) 501,280 486,447 144,078
Number of shares, Granted (in shares) 5,682 116,705 407,712
Number of shares, Vested (in shares) (162,381) (101,872) (65,343)
Number of shares, Forfeited (in shares) (66,000) 0 0
Number of shares, Nonvested, Ending (in shares) 278,581 501,280 486,447
Summary of restricted stock activity, weighted average grant-date fair value [Roll Forward]      
Weighted Average Grant-Date Fair Value, Nonvested, Beginning (in dollars per share) $ 7.67 $ 5.86 $ 4.50
Weighted Average Grant-Date Fair Value, Granted (in dollars per share) $ 15.43 $ 13.38 $ 6.21
Weighted Average Grant-Date Fair Value, Vested (in dollars per share) $ 7.45 $ 5.48 $ 5.10
Weighted Average Grant-Date Fair Value, Forfeited (in dollars per share) $ 5.99 $ 0.00 $ 0.00
Weighted Average Grant-Date Fair Value, Nonvested, Ending (in dollars per share) $ 8.13 $ 7.67 $ 5.86