Allowance for Loan and Lease Losses (Composition of the Company's allowance for loan and lease losses) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 167,509	$ 115,937
Acquired BBVAPR loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	49,617	35,356
Acquired BBVAPR Accounted for under ASC 310-20 [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	3,862	4,300
Acquired BBVAPR Accounted for under ASC 310-20 [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	42	169
Acquired BBVAPR Accounted for under ASC 310-20 [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	3,225	3,028
Acquired BBVAPR Accounted for under ASC 310-20 [Member] | Auto Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	595	1,103
Acquired BBVAPR accounted under ASC 310-30 [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	45,755	31,056
Acquired BBVAPR accounted under ASC 310-30 [Member] | Mortgage Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	14,085	2,682
Acquired BBVAPR accounted under ASC 310-30 [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	23,691	23,452
Acquired BBVAPR accounted under ASC 310-30 [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	18	0
Acquired BBVAPR accounted under ASC 310-30 [Member] | Auto Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	7,961	4,922
Eurobank Acquired Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	25,174	21,281
Originated Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	92,718	59,300
Originated Loan [Member] | Mortgage Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	20,439	17,344
Originated Loan [Member] | Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	30,258	8,995
Originated Loan [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	16,454	13,067
Originated Loan [Member] | Auto and Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	25,567	19,463
Originated Loan [Member] | Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	0	431
Acquired loans [Member] | Eurobank Acquired Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	25,174	21,281
Acquired loans [Member] | Eurobank Acquired Loans | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	5	6
Acquired loans [Member] | Eurobank Acquired Loans | Loans secured by 1-4 family residential properties, covered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	15,187	11,947
Acquired loans [Member] | Eurobank Acquired Loans | Commercial and Other Construction Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 9,982	$ 9,328