Earnings per Share - Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Diluted Net Income Allocated to:
Total Diluted Net Income Attributable to Shareholders		$ 21,176	$ 9,997	$ 40,906	$ 10,749
Total Basic Weighted-Average Shares Outstanding (in shares)	[1]	17,255,593	17,215,163	17,248,045	17,502,674
Dilutive Effect of B Units (in shares)		55,286,341	54,207,113	55,355,592	54,046,330
Dilutive Effect of Options (in shares)		1,793,668		1,486,643	13,065
Dilutive Effect of Phantom Class B Units & Phantom Shares of Class A Common Stock (in shares)		2,728,652	1,301,360	2,571,352	1,754,097
Dilutive Effect of Restricted Shares of Class A Common Stock (in shares)		33,018	5,459	31,456	9,873
Diluted Weighted Average Common Shares Outstanding (in shares)		77,097,272	72,729,095	76,693,088	73,326,039
Participating Class B Units and Class B-1 Units (in shares)		7,239,297	5,879,102	7,239,297	5,935,009
Diluted Weighted-Average Shares Outstanding (in shares)	[1]	84,336,569	78,608,197	83,932,385	79,261,048
Diluted Earnings per Share (in dollars per share)	[2]	$ 0.25	$ 0.13	$ 0.49	$ 0.13
Options to Purchase Class B Units
Diluted Net Income Allocated to:
Antidilutive securities excluded from diluted EPS (in shares)		400,000	5,500,000	400,000	5,500,000
Options to Purchase Shares of Class A Common Stock
Diluted Net Income Allocated to:
Antidilutive securities excluded from diluted EPS (in shares)		200,000	200,000	200,000	200,000
Contingent Options to Purchase Shares of Class A Common Stock
Diluted Net Income Allocated to:
Antidilutive securities excluded from diluted EPS (in shares)		1,000,000.0	1,000,000.0	1,000,000.0	1,000,000.0
Common Class A
Diluted Net Income Allocated to:
Total Diluted Net Income Attributable to Shareholders		$ 19,249	$ 9,236	$ 37,186	$ 9,925
Total Basic Weighted-Average Shares Outstanding (in shares)		17,233,829	17,203,898	17,227,164	17,497,041
Participating Shares of Restricted Class A Common Stock
Diluted Net Income Allocated to:
Total Diluted Net Income Attributable to Shareholders		$ 6	$ 1	$ 11	$ 1
Total Basic Weighted-Average Shares Outstanding (in shares)	[3]	21,764	11,265	20,881	5,633
Participating Class B Units
Diluted Net Income Allocated to:
Total Diluted Net Income Attributable to Shareholders		$ 1,921	$ 760	$ 3,709	$ 823

[1] ^{The Company issues restricted shares of Class A common stock and restricted Class B units that have non-forfeitable dividend rights.  Under the "two-class method," these shares and units are considered participating securities and are required to be included in the computation of basic and diluted earnings per share.}

[2] ^{During the six months ended June 30, 2020, the calculation of diluted earnings per share resulted in an increase in earnings per share. Therefore, diluted earnings per share is assumed to be equal to basic earnings per share. Please refer to Note 5, “Earnings per Share,” for further details.}

[3] Certain unvested shares of Class A common stock granted to employees have nonforfeitable rights to dividends and therefore participate fully in the results of the Company from the date they are granted. They are included in the computation of basic earnings per share using the two-class method for participating securities.