Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

Share-based Compensation [Abstract]

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

			Weighted-		Weighted-
			average		average		Aggregate
	Number		grant date		contractual		intrinsic
	of shares		fair value		life		value
Restricted Stock Awards
Outstanding, beginning of year		1,437	$	32.91
Awarded		398		44.73
Vested		(271)		28.30
Forfeited		(6)		40.70
Outstanding, end of year		1,558		36.70		1.6 years	$	83,383
Restricted Stock Units
Outstanding, beginning of year		135	$	33.91
Awarded		13		45.17
Vested		(9)		28.41
Outstanding, end of year		139		35.31		1.1 years	$	7,457
Expected to vest, end of year		132				1.0 years		7,069

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	2014			2013			2012
Fair value of options granted	$	6.51		$	7.17		$	7.89
Risk free interest rate		1.4	%		1.0	%		1.1	%
Expected volatility		18.4	%		23.0	%		31.4	%
Expected dividend yield		2.1	%		1.8	%		2.1	%
Expected option life		4.1 years			4.9 years			6.6 years

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

			Weighted-		Weighted-
			average		average		Aggregate
	Number		exercise		contractual		intrinsic
	of shares		price		life		value
Outstanding, beginning of year		1,293	$	29.50
Granted		10		52.51
Exercised		(461)		25.66
Forfeited and expired		(40)		37.28
Outstanding, end of year		802		31.61		4.2 years	$	17,575
Vested or expected to vest, end of year		771		31.49		4.2 years		16,983
Exercisable, end of year		311		29.26		3.7 years		7,554