Condensed Financial Statements of BankUnited, Inc. (Schedule of Condensed Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Investment securities									$ 152,619	$ 193,856	$ 280,560
Interest Expense - Borrowings									96,164	115,871	143,905
Employee compensation and benefits									243,532	217,156	235,330
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									449,385	249,359	403,996
Provision for income taxes	$ (61,724)	$ 27,459	$ 36,176	$ 32,490	$ 21,228	$ 19,353	$ 20,396	$ (9,471)	34,401	51,506	90,898
Net income	$ 125,255	$ 86,941	$ 103,974	$ 98,814	$ 85,737	$ 66,559	$ 76,508	$ (30,951)	414,984	197,853	313,098
Parent Company
Condensed Income Statements, Captions [Line Items]
Investment securities									4,958	4,214	3,595
Service fees from subsidiaries									13,014	15,935	18,080
Equity in earnings of subsidiaries									455,672	224,734	335,723
Other Income									(2,530)	3,822	2,690
Total Income									471,114	248,705	360,088
Interest Expense - Borrowings									36,143	29,041	20,200
Employee compensation and benefits									26,730	24,867	28,270
Other Expenses									3,744	3,711	4,396
Total expense									66,617	57,619	52,866
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									404,497	191,086	307,222
Provision for income taxes									(10,487)	(6,767)	(5,876)
Net income									$ 414,984	$ 197,853	$ 313,098