Income Tax Provision (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Provision
Income tax provision	$ 6,789,000	$ 5,384,000
Pretax income	19,902,000	16,973,000
Effective tax rate (as a percent)	34.10%	31.70%
Unrecognized tax benefit	3,700,000		3,700,000
Uncertain tax positions	38,000
Interest expense associated with unrecognized tax benefits	27,000
Accrued interest payable associated with unrecognized tax benefits	$ 395,000		$ 368,000