Stock Options (Schedule of Restricted Stock Award Activity) (Details) - Restricted Stock - $ / shares		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)		32,616	12,043	10,724
Granted (in shares)		27,440	26,004	6,000
Exercised (in shares)		(11,909)	(5,431)	(4,681)
Canceled (in shares)		(2,526)	0	0
Outstanding at end of year (in shares)		45,621	32,616	12,043
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value [Roll Forward]
Outstanding at beginning of year (in dollars per share)	[1]	$ 53.31	$ 44.10	$ 32.49
Granted (in dollars per share)	[1]	55.17	54.14	53.51
Exercised (in dollars per share)	[1]	52.67	36.85	29.56
Canceled (in dollars per share)	[1]	53.57	0.00	0.00
Outstanding at end of year (in dollars per share)	[1]	$ 54.58	$ 53.31	$ 44.10

[1] Weighted Averages