Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

The following table represents stock options activity for the year ended December 31, 2015:

	Number of Shares		Weighted Average Exercise Price		Average Remaining Contractual Term	Aggregate Intrinsic Value
Options outstanding at January 1, 2015	15,000		$	16.88	1.0 year	$	214,575
Options granted	—		—		—	—
Options exercised	(9,500	)	15.21		—	—
Options forfeited or expired	—		—		—	—
Options outstanding at December 31, 2015	5,500		$	20.09	0.5 years	$	—
Options exercisable at December 31, 2015	5,500		$	20.09	0.5 years	$	140,470

Nonvested Stock Activity

The following table represents the nonvested stock activity for the year ended December 31, 2015:

	Number of Shares		Weighted Average Grant Date Fair Value
Nonvested shares outstanding at January 1, 2015	524,287		$	22.56
Granted	199,065		34.06
Vested	(177,887	)	23.28
Forfeited	(18,374	)	20.57
Nonvested shares outstanding at December 31, 2015	527,091		$	26.64

Summary of Shares Issued Under Employee Stock Purchase Plan

The following table represents the shares issued during 2015, 2014 and 2013 under the Employee Stock Purchase Plan:

	Number of Shares	Weighted Average Per Share Price
Shares available as of January 1, 2012	61,247
Additional shares authorized for issuance	250,000
Shares issued in 2013	38,459	$	20.39
Shares issued in 2014	36,305	$	21.49
Shares issued in 2015	22,723	$	34.37
Shares available as of December 31, 2015	213,760