Fair Value Measurements - Reconciliation of Assets with Unobservable Inputs (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 16,536,000	$ 13,907,000	$ 13,944,000	$ 12,829,000
Change included in earnings	(3,390,000)	(1,236,000)	(9,466,000)	(3,836,000)
Purchases and issuances	16,927,000	5,641,000	43,725,000	15,537,000
Sales and settlements	(11,679,000)	(4,725,000)	(29,809,000)	(10,943,000)
Ending balance	18,394,000	13,587,000	18,394,000	13,587,000
Net change in unrealized gains (losses) relating to items held at end of period	6,519,000	1,363,000	6,519,000	1,363,000
Net change in unrealized gains (losses) included in other comprehensive income	0	0	0	0
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	10,721,000	10,836,000	11,920,000	10,821,000
Change included in earnings	(1,505,000)	(663,000)	(4,363,000)	(2,287,000)
Purchases and issuances	1,373,000	1,033,000	3,032,000	2,672,000
Sales and settlements	0	0	0	0
Ending balance	10,589,000	11,206,000	10,589,000	11,206,000
Net change in unrealized gains (losses) relating to items held at end of period	0	0	0	0
Commercial servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,162,000	999,000	1,214,000	1,030,000
Change included in earnings	(101,000)	(20,000)	(180,000)	(118,000)
Purchases and issuances	225,000	39,000	252,000	106,000
Sales and settlements	0	0	0	0
Ending balance	1,286,000	1,018,000	1,286,000	1,018,000
Net change in unrealized gains (losses) relating to items held at end of period	0	0	0	0
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4,653,000	2,072,000	810,000	978,000
Change included in earnings	(1,784,000)	(553,000)	(4,923,000)	(1,431,000)
Purchases and issuances	15,329,000	4,569,000	40,441,000	12,759,000
Sales and settlements	(11,679,000)	(4,725,000)	(29,809,000)	(10,943,000)
Ending balance	6,519,000	1,363,000	6,519,000	1,363,000
Net change in unrealized gains (losses) relating to items held at end of period	$ 6,519,000	$ 1,363,000	$ 6,519,000	$ 1,363,000