Summary of Significant Accounting Policies - Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Numerator:
Net income	$ 26,647	$ 6,929
Denominator:
Basic weighted average shares (in shares)	9,107,234	9,027,934
Dilutive common stock equivalents using treasury stock method	107,451	243,877
Diluted weighted average shares (in shares)	9,214,685	9,271,811
Basic earnings per common share: (in dollars per share)	$ 2.93	$ 0.77
Diluted earnings per common share: (in dollars per share)	$ 2.89	$ 0.75
Weighted average options outstanding	1,197,487	1,137,219
Anti-dilutive options not included in the computations	681,820	893,343