Loan Servicing Rights - Summary of Loan Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance, beginning of period	$ 38,816	$ 18	$ 56,313	$ 23
Acquired in the Merger	0	59,567	0	59,567
New servicing assets created	5,280	1,906	11,238	1,906
Impairment (charge) recovery	(154)	(4,520)	(17,248)	(4,520)
Amortization	(5,689)	(1,670)	(12,050)	(1,675)
Balance, end of period	38,253	55,301	38,253	55,301
Valuation allowance, end of period	(21,131)	(4,520)	(21,131)	(4,520)
Loans serviced for others that have servicing rights capitalized, end of period	$ 6,179,464	$ 6,647,153	$ 6,179,464	$ 6,647,153