Nature of Operations and Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2019 USD ($) quarter step reporting_unit operating_segment division	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2020 USD ($)
Number of Bank Divisions | division	16
Number of Operating Segments | operating_segment	1
Total assets	$ 13,683,999,000	$ 12,115,484,000
Gross loans	$ 9,512,810,000	8,287,549,000
Maximum Period of Original Maturity to be Included in Cash and Cash Equivalents	three months
Federal Reserve Balance or Cash on Hand Required	$ 50,055,000
Minimum Period Past Due to Consider Loans as Delinquent	30 days
Minimum Period Past Due to Consider Loans as Non Accrual	90 days
Number of Quarters Used to Evaluate Historical Loss Experience | quarter	12
Minimum Number of Days Delinquent to Charge off Loans	120 days
Maximum Term Leases Will Be Considered Short-term	12 months
Maximum period up to which purchase price of business is allocated to assets acquired and liabilities assumed	1 year
Number of Reporting Units Subsequent to Aggregation for Goodwill Assessment | reporting_unit	1
Number of steps included in goodwill impairment test | step	2
Revenue from Contracts with Customers	$ 69,877,000	76,664,000	$ 69,808,000
Impairment losses on receivables related to contracts with customers	$ 0	$ 0
Percentage of likelihood for term more likely than not as it relates to income taxes	50.00%
State Bank of Arizona
Total assets	$ 677,654,000
Gross loans	439,237,000
Total deposits	586,688,000
Accounting Standards Update 2017-08
Effect of cumulative change on retained earnings from applying new accounting pronouncement	24,102,000
Accounting Standards Update 2016-02
Effect of cumulative change on assets from applying new accounting pronouncement	36,178,000
Effect of cumulative change on liabilities from applying new accounting pronouncement	$ 38,220,000
Minimum Range
Number of years for home equity loan origination term	10
Minimum Range | Accounting Standards Update 2016-13 | Forecast
Estimated ACL upon adoption of the new accounting standard				$ 125,600,000
Estimated allowance for unfunded commitments upon adoption of the new accounting standard				12,800,000
Estimated effect of cumulative change on retained earnings from applying new accounting pronouncement				9,955,000
Minimum Range | Office Buildings
Useful life of premises and equipment	15 years
Minimum Range | Furniture, fixtures and equipment
Useful life of premises and equipment	3 years
Maximum Range
Number of years for home equity loan origination term	15 years
Maximum Range | Accounting Standards Update 2016-13 | Forecast
Estimated ACL upon adoption of the new accounting standard				131,300,000
Estimated allowance for unfunded commitments upon adoption of the new accounting standard				13,600,000
Estimated effect of cumulative change on retained earnings from applying new accounting pronouncement				$ 14,808,000
Maximum Range | Office Buildings
Useful life of premises and equipment	40 years
Maximum Range | Furniture, fixtures and equipment
Useful life of premises and equipment	10 years