Supplemental Financial Information Quarterly Results (unaudited) - Schedule of Unaudited Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenues	$ 106,700	$ 87,000	$ 56,100	$ 51,200	$ 89,100	$ 86,800	$ 88,500	$ 87,500	$ 301,012	$ 351,985	$ 239,182
Total operating expenses	65,400	61,800	62,500	65,500	67,500	66,100	69,000	68,500	255,169	271,117	232,282
Total operating income	41,300	25,200	(6,400)	(14,300)	21,600	20,700	19,500	19,000	45,843	80,868	6,900
Interest expense	5,200	5,700	10,600	5,800	5,900	5,700	5,600	5,300	27,420	22,438	7,198
Income (loss) before taxes	36,100	19,500	(17,000)	(20,100)	15,700	15,000	13,900	13,700	18,423	58,430	(298)
Provision (benefit) for taxes	11,900	4,500	(4,300)	(4,700)	4,700	3,800	3,300	7,400	7,445	19,208	26,353
Net income (loss)	$ 24,200	$ 15,000	$ (12,700)	$ (15,400)	$ 11,000	$ 11,200	$ 10,600	$ 6,300	$ 10,978	$ 39,222	$ (26,651)
Earnings (loss) per share:
Basic (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.46	$ 0.45	$ 0.39	$ 0.21	$ 0.46	$ 1.46	$ (0.83)
Diluted (usd per share)	$ 1.05	$ 0.63	$ (0.53)	$ (0.64)	$ 0.45	$ 0.43	$ 0.38	$ 0.21	$ 0.45	$ 1.42	$ (0.83)