Income Taxes (Details Textual) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Deferred Tax Assets Tax Deferred Compensation Noncurrent	$ 1,082,000				$ 1,074,000				$ 1,082,000	$ 1,074,000
Income Tax Expense (Benefit)	3,265,000	$ 3,715,000	$ 3,390,000	$ 2,130,000	2,450,000	$ 2,599,000	$ 3,141,000	$ 1,450,000	12,500,000	9,640,000	$ 10,050,000
Income Tax Examination, Penalties and Interest Accrued	$ 0				$ 0				$ 0	0	$ 0
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Value										893,000
Adjustments Related to Tax Withholding for Share-based Compensation										$ 360,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period										59,000