Segment Information - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Adjusted EBITDA									$ 92,558	$ 103,515	$ 104,316
Gain (loss) on sale or disposition of assets									(503)	(342)	139
Impairment charge - leased assets									(7,902)	0	0
Equity-based compensation expense									(16,267)	(10,934)	(9,176)
Acquisition-related expense									(2,375)	(1,127)	(1,634)
Gain on reduction in tax receivable agreement liability											6,145
Special Committee investigation and remediation expense											(2,862)
Fair value adjustments to contingent consideration									(814)	(241)	1,289
Interest income									340	1,446	676
Interest expense									(9,223)	(12,229)	(12,051)
Depreciation and amortization									(26,691)	(22,323)	(20,678)
Income before provision for income taxes	$ 4,638	$ 8,775	$ 6,630	$ 9,080	$ 7,564	$ 20,717	$ 19,319	$ 10,165	29,123	57,765	66,164
Total Real Estate
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Adjusted EBITDA									96,079	106,810	108,669
Mortgage
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Adjusted EBITDA									(2,255)	(2,709)	(3,436)
Other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated
Adjusted EBITDA									$ (1,266)	$ (586)	$ (917)