Summary of Significant Accounting Policies, Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]
Stock options outstanding (in shares)	748				661				748	661	503
Antidilutive shares and options excluded from computation of earnings per share (in shares)									129	343	352
Net income	$ 6,676	$ 6,717	$ 7,842	$ 8,351	$ 4,916	$ 1,361	$ 5,560	$ 4,466	$ 29,586	$ 16,303	$ 12,993
Weighted average shares outstanding (in shares)									24,001	23,877	23,781
Basic income per share (in dollars per share)									$ 1.23	$ 0.68	$ 0.55
Effect of stock options outstanding [Abstract]
Assumed exercise, at the strike price at the beginning of year (in shares)									485	343	231
Assumed repurchase of shares under treasury stock method (in shares)									(371)	(201)	(186)
Diluted weighted average shares (in shares)									24,115	24,019	23,826
Diluted income per share (in dollars per share)									$ 1.23	$ 0.68	$ 0.55