Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Share-based Compensation [Abstract]

Summary of Stock Option Activity [Table Text Block]

	2015	2014	2013
Number of shares under the plans:
Outstanding and exercisable at beginning of year	7,500	18,750	22,500
Granted	-	-	-
Canceled	-	-	-
Exercised	(7,500)	(11,250)	(3,750)
Outstanding and exercisable at end of year	-	7,500	18,750

Schedule of Nonvested Share Activity [Table Text Block]

	Restricted	Performance		Weighted Average
	Stock	Stock		Grant Date
	Units	Units		Fair Value
Outstanding at January 1, 2013	176,646	59,725	$	31.65
Granted	12,973	31,418		42.49
Vested	(41,579)	-		29.18
Adjustment for incentive awards not expected to vest	-	(18,408)		35.84
Canceled	(18,314)	(11,084)		33.55
Outstanding at December 31, 2013	129,726	61,651	$	34.00
Granted	19,051	34,652		44.07
Vested	(40,540)	(13,588)		34.59
Adjustment for incentive awards not expected to vest	-	(7,845)		43.59
Canceled	-	(2,880)		44.13
Outstanding at December 31, 2014	108,237	71,990	$	36.25
Granted	29,656	41,114		44.93
Vested	(39,076)	(23,877)		32.35
Adjustment for incentive awards not expected to vest	-	(53,228)		43.26
Canceled	(5,000)	-		44.84
Outstanding at December 31, 2015	93,817	35,999	$	39.66

Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]

	2015	2014	2013
Number of shares available for future grant:
Beginning of year	469,840	513,280	517,280
End of year	407,307	469,840	513,280