Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Allowance for loan losses	$ 103,267	$ 93,580
Net unrealized losses on AFS debt securities	0	19,704
Share-based compensation expense	14,233	10,642
State income taxes	16,097	13,854
Accrued compensation	22,578	8,291
Deferred rent	0	7,940
Lease liability	60,635	0
Other accruals	12,383	7,061
Net operating loss	6,386	2,447
Goodwill and intangibles	3,141	0
Other	7,923	11,339
Deferred tax assets	246,643	174,858
Valuation allowance	(5,919)	(2,107)
Net deferred tax assets after valuation allowance	240,724	172,751
Deferred tax liabilities:
Derivative equity warrant assets	(45,533)	(32,861)
Change in accounting method (section 481(a))	(1,841)	(8,034)
Net unrealized gains on AFS debt securities	(33,480)	0
Non-marketable and other equity securities	(54,239)	(45,759)
Premises and equipment and other intangibles	(16,459)	(10,284)
Right-of-use asset and deferred rent assets	(50,493)	0
Other	(10,246)	(10,380)
Deferred tax liabilities	(212,291)	(107,318)
Net deferred tax assets	$ 28,433	$ 65,433