12. Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

QuarterEnded	OperatingRevenue		OperatingIncome		Net Income		Income  Per Basic Share		Income  Per Diluted Share
	(In thousands, except per share amounts)
03/31/18	$	39,401	$	11,366	$	8,487	$	4.58	$	4.57
06/30/18		38,847		11,266		8,797		4.75		4.74
09/30/18		39,274		10,757		9,221		4.98		4.96
12/31/18		34,926		8,318		7,749		4.18		4.17
03/31/17	$	38,504	$	11,327	$	9,950	$	5.42	$	5.36
06/30/17		36,164		10,175		10,026		5.44		5.40
09/30/17		37,903		11,479		7,971		4.30		4.29
12/31/17		34,024		8,293		8,646		4.67		4.66

The quarterly information presented above reflects, in the opinion of management, all adjustments necessary for a fair presentation of the results for the interim periods presented.