Segment Reporting - Reconciliation of Operating Profit (Loss) from Segments to Consolidated (Details) - USD ($) $ 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
Reconciliation of income from continuing operations from segments to consolidated [Abstract]
Total consolidated operating income	$ 22,880	$ 25,359	$ 24,020	$ 24,787	$ 26,994	$ 28,329	$ 21,169	$ 16,754	$ 97,046	$ 93,246	$ 46,510
Interest expense									(29,468)	(34,847)	(38,237)
Other									3,461	3,713	4,984
Income before income taxes									$ 71,039	$ 62,112	$ 13,257