Regulatory Requirements and Restrictions (Schedule of Compliance with Regulatory Capital Requirements Under Banking Regulations) (Details) $ / unit in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) $ / unit	Dec. 31, 2017 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Document Fiscal Year Focus	2018
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital	$ 2,839,302	$ 2,892,069
Tier One Leverage Capital to Average Assets	8.99%	9.72%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,263,725	$ 1,189,944
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Common Equity Tier One Risk Based Capital	$ 2,839,302	$ 2,892,069
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	12.57%	13.11%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized	$ 1,467,693	$ 1,434,193
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy	$ 1,016,095	$ 992,903
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier One Risk Based Capital	$ 2,839,302	$ 2,892,069
Tier One Risk Based Capital to Risk Weighted Assets	12.57%	13.11%
Tier One Risk Based Capital Required to be Well Capitalized	$ 1,806,392	$ 1,765,161
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	$ 1,354,794	$ 1,323,871
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Capital	$ 2,952,464	$ 3,041,004
Capital to Risk Weighted Assets	13.08%	13.78%
Capital Required to be Well Capitalized	$ 2,257,990	$ 2,206,451
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Capital Required to be Well Capitalized to Risk Weighted Assets	$ 1,806,392	$ 1,765,161
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Capital conservation buffer required for Common equity tier one | $ / unit	1,580,593
Capital conservation buffer required for Common equity tier one ratio	7.00%
Capital conservation buffer required for tier one risk based | $ / unit	1,919,291
Capital conservation buffer required for tier one risk based ratio	8.50%
Capital required under capital conservation buffer | $ / unit	2,370,889
Capital required under capital conservation buffer ratio	10.50%
BankUnited [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Leverage Capital	$ 3,026,106	$ 3,107,920
Tier One Leverage Capital to Average Assets	9.60%	10.47%
Tier One Leverage Capital Required to be Well Capitalized	$ 1,575,712	$ 1,483,796
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,260,569	$ 1,187,037
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Common Equity Tier One Risk Based Capital	$ 3,026,106	$ 3,107,920
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	13.45%	14.13%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized	$ 1,462,054	$ 1,429,999
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy	$ 1,012,191	$ 989,999
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Tier One Risk Based Capital	$ 3,026,106	$ 3,107,920
Tier One Risk Based Capital to Risk Weighted Assets	13.45%	14.13%
Tier One Risk Based Capital Required to be Well Capitalized	$ 1,799,451	$ 1,759,999
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	$ 1,349,588	$ 1,319,999
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Capital	$ 3,139,268	$ 3,255,221
Capital to Risk Weighted Assets	13.96%	14.80%
Capital Required to be Well Capitalized	$ 2,249,314	$ 2,199,999
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Capital Required to be Well Capitalized to Risk Weighted Assets	$ 1,799,451	$ 1,759,999
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Capital conservation buffer required for Common equity tier one	1,574,519
Capital conservation buffer required for Common equity tier one ratio	7.00%
Capital conservation buffer required for tier one risk based | $ / unit	1,911,917
Capital conservation buffer required for tier one risk based ratio	8.50%
Capital required under capital conservation buffer | $ / unit	2,361,779
Capital required under capital conservation buffer ratio	10.50%