Segment Information (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended
	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment					2
Revenues from external customers
Revenues from external customers		$ 85,776	$ 88,900		$ 257,991	$ 257,103
Operating income
Operating income		8,517	16,482		39,223	47,545
Interest expense		2,356	4,446		11,491	12,794
Loss on extinguishment of debt	$ 3,200	0	0		3,196	0
Other expense (income)		804	(799)		(1,695)	(2,055)
Income before income taxes		5,357	12,835		26,231	36,806
U.S.
Revenues from external customers
Revenues from external customers		74,650	70,255		225,274	215,829
Operating income
Operating income		6,389	12,897	$ 33,662		41,345
International
Revenues from external customers
Revenues from external customers		11,126	18,645		$ 32,717	41,274
Operating income
Operating income		$ 2,128	$ 3,585	$ 5,561		$ 6,200