Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 7,115,567	$ 7,340,288	$ 7,021,492
Liabilities	5,520,371	5,436,712
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	173,700	178,400
Liabilities	$ 172,100	$ 176,700