Stock-Based Compensation Plans Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Options Shares [Abstract]
Outstanding at beginning of year	1,357,498
Granted	362,903
Exercised	(167,663)
Expired	(33,240)
Forfeited	(41,872)
Outstanding at end of year	1,477,626	1,357,498
Exercisable at end of year	789,818
Weighted Average Exercise Price [Abstract]
Beginning of year	$ 77.12
Granted	73.98
Exercised	61.44
Expired	90.47
Forfeited	69.57
End of year	78.04	$ 77.12
Exercisable at end of year	$ 85.88
Weighted Average Remaining Contractual Term, Outstanding at end of year	2 years 7 months 6 days
Weighted Average Remaining Contractual Term, Exercisable at end of year	1 year 9 months 18 days
Aggregate Intrinsic Value, Outstanding at end of year	$ 10,811
Aggregate Intrinsic Value, Exercisable at end of year	$ 3,503
Weighted average grant date fair value of options	$ 19.38	$ 17.37	$ 18.47
Total intrinsic value of options exercised during the year	$ 1,500	$ 1,600	$ 4,700