Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2015

Share-based Compensation [Abstract]

Schedule of Share-based Compensation, Common Stock, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

		Weighted-average
	Number	grant date		Aggregate		Vesting
	of shares	fair value		fair value		period
Common stock	23	$	58.17	$	1,323	None
Restricted stock	314		55.91		17,548	1 - 4 years
Restricted stock units	6		56.43		349	4 years