Variable Interest Entities - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018
Variable Interest Entity [Line Items]
Investment in variable interest entities	$ 64,535	$ 69,459	$ 67,898
Advances to variable interest entities	17,239	5,783	12,375
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investment in variable interest entities	57,541	64,281	63,021
Advances to variable interest entities	14,500	3,273	9,937
Guaranteed amounts to variable interest entities (not to exceed)	$ 63,584	$ 67,027	$ 71,919