Summary of Significant Accounting Policies (Weighted-Average Number of Shares Used in Computing Earnings Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Weighted average basic shares outstanding (in shares)	12,211,978	12,126,264	12,215,425
Plus dilutive impact of employee stock awards (in shares)	243,963	148,188	167,526
Weighted average diluted shares outstanding (in shares)	12,455,941	12,274,452	12,382,951