Overview - Schedule of Shares and Operating Group Units (Detail) - shares	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Class A Shares
Class of Stock
Common stock and operating group units outstanding	22,311,432	21,946,639	21,284,945	20,631,750	20,484,430	19,905,126
Class B Shares
Class of Stock
Common stock and operating group units outstanding	32,820,414	32,845,414	29,208,952	29,208,952	29,208,952	29,458,948
Group A Units
Class of Stock
Common stock and operating group units outstanding	16,019,506
Group A-1 Units
Class of Stock
Common stock and operating group units outstanding	9,779,446
Group B Units
Class of Stock
Common stock and operating group units outstanding	22,311,432
Group E Units
Class of Stock
Common stock and operating group units outstanding	13,450,821
Group P Units
Class of Stock
Common stock and operating group units outstanding	3,385,000