Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

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

The following table presents stock options outstanding under these plans (in thousands, except for per share data):

	Number	Weighted- Average Exercise Price		Aggregate Intrinsic Value
Options outstanding at:
December 31, 2016	218,524	51.95		6,793
December 31, 2017	117,551	53.26		4,592
December 31, 2018	63,058	$	54.89	$	1,163
Options vested at:
December 31, 2016	93,117	$	46.22	$	3,429
December 31, 2017	51,286	48.62		2,241
December 31, 2018	33,573	53.09		679

Schedule of Nonvested Share Activity [Table Text Block]

The following represents a summary of the non-vested stock awards for the three years ended December 31, 2018 (in thousands):

	Shares		Weighted Average Grant Date Fair Value
Non-vested at January 1, 2016	791,109
Granted	256,670		$55.35
Vested	(213,941	)	$55.87
Forfeited	(47,132	)	$57.86
Non-vested at December 31, 2016	786,706
Granted	177,807		$86.95
Vested	(194,419	)	$63.07
Forfeited	(102,991	)	$78.70
Non-vested at December 31, 2017	667,103
Granted	150,419		$85.58
Vested	(242,215	)	$74.85
Forfeited	(47,700	)	$75.68
Non-vested at December 31, 2018	527,607