Summarized Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Summarized Quarterly Financial Data (Unaudited) [Abstract]

Schedule of quarterly financial information

Quarterly financial information for 2016 and 2017 is as follows (in thousands except per share data):

	Quarter
2016	First		Second		Third		Fourth
Revenues	$	111,166	$	108,487	$	102,156	$	119,279
Income from operations		20,092		12,896		4,830		19,654
Net income		12,420		7,786		2,878		11,718
Net income per share:
Basic	$	1.17	$	0.73	$	0.27	$	1.10
Diluted	$	1.15	$	0.72	$	0.27	$	1.07

	Quarter
2017	First		Second		Third		Fourth
Revenues	$	114,912	$	112,720	$	108,512	$	118,707
Income from operations		18,443		13,854		8,224		11,688
Net income (loss)		10,578		10,302		6,227		(6,495)
Net income (loss) per share:
Basic	$	1.00	$	0.96	$	0.58	$	(0.61)
Diluted	$	0.95	$	0.92	$	0.56	$	(0.61)