Loans Receivable and Allowance for Loan Losses - Troubled Debt Restructurings on Financing Receivables (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) loan	Mar. 31, 2016 USD ($) loan	Dec. 31, 2016 USD ($) loan
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 66,105,000		$ 70,870,000
Number of modified contracts \| loan	6	8
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 2,905,000	$ 13,317,000
Post-Modification	$ 2,358,000	$ 8,654,000
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	2	9
Balance	$ 113,000	$ 3,063,000
Specific reserves	2,000	2,100,000
Specific reserves for the TDRs	10,000	144,000
Charge offs	0	$ 30,000
Specific reserves allocated to TDRs	3,800,000		5,300,000
Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	20,255,000		22,521,000
Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	32,186,000		33,641,000
Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	13,664,000		14,708,000
TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	48,984,000		48,874,000
TDR on accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	16,482,000		16,387,000
TDR on accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	24,770,000		23,911,000
TDR on accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	7,732,000		8,576,000
TDR on non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	17,121,000		21,996,000
TDR on non-accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	3,773,000		6,134,000
TDR on non-accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	7,416,000		9,730,000
TDR on non-accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 5,932,000		6,132,000
Commercial & industrial \| TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured			$ 25,054,000
Number of modified contracts \| loan	20		20
Real estate \| Commercial & industrial \| TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 24,619,000		$ 25,054,000
Real estate \| Commercial & industrial \| TDR on accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	16,249,000		16,358,000
Real estate \| Commercial & industrial \| TDR on accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	2,302,000		1,840,000
Real estate \| Commercial & industrial \| TDR on accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	6,068,000		6,856,000
Real estate \| Commercial & industrial \| TDR on non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	9,844,000		11,320,000
Real estate \| Commercial & industrial \| TDR on non-accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	2,503,000		4,417,000
Real estate \| Commercial & industrial \| TDR on non-accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	1,774,000		1,313,000
Real estate \| Commercial & industrial \| TDR on non-accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	5,567,000		5,590,000
Commercial business \| TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 19,781,000		$ 19,165,000
Number of modified contracts \| loan	24		23
Commercial business \| TDR on accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 233,000		$ 29,000
Commercial business \| TDR on accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	17,969,000		17,471,000
Commercial business \| TDR on accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	1,579,000		1,665,000
Commercial business \| TDR on non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	6,424,000		8,234,000
Commercial business \| TDR on non-accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	1,270,000		1,717,000
Commercial business \| TDR on non-accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	4,789,000		6,130,000
Commercial business \| TDR on non-accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	365,000		387,000
Trade Finance and Other \| TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	4,584,000		4,655,000
Trade Finance and Other \| TDR on accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	0		0
Trade Finance and Other \| TDR on accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	4,499,000		4,600,000
Trade Finance and Other \| TDR on accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	85,000		55,000
Trade Finance and Other \| TDR on non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	853,000		2,442,000
Trade Finance and Other \| TDR on non-accrual \| Payment concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	0		0
Trade Finance and Other \| TDR on non-accrual \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	853,000		2,287,000
Trade Finance and Other \| TDR on non-accrual \| Rate concession
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	0		155,000
Consumer and other \| TDR on accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructured	$ 4,584,000		$ 4,655,000
Number of modified contracts \| loan	24		19
Legacy
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	3	7
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 2,163,000	$ 13,287,000
Post-Modification	$ 1,700,000	$ 8,625,000
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	1	8
Balance	$ 102,000	$ 3,001,000
Legacy \| Real estate
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Real estate \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans		2
Balance		$ 729,000
Legacy \| Real estate \| Retail
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Real estate \| Hotel & motel
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Real estate \| Gas station & car wash
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	2
Balance	$ 0	$ 729,000
Legacy \| Real estate \| Mixed use
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Real estate \| Industrial & warehouse
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Real estate \| Other
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	1	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 482,000	$ 0
Post-Modification	$ 482,000	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Commercial business
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	2	6
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 1,681,000	$ 11,088,000
Post-Modification	$ 1,218,000	$ 7,039,000
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	1	6
Balance	$ 102,000	$ 2,272,000
Legacy \| Commercial business \| Payment concession
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans	1	4
Balance	$ 102,000	$ 2,022,000
Legacy \| Commercial business \| Troubled Debt Restructuring Concession, Type, Maturity/ Amortization Concession [Member]
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans		2
Balance		$ 249,000
Legacy \| Trade finance
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	1
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 2,199,000
Post-Modification	$ 0	$ 1,586,000
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Consumer And Other Portfolio Segment [Member]
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Legacy \| Consumer and other
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Acquired
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	3	1
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 742,000	$ 30,000
Post-Modification	$ 658,000	$ 29,000
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	1	1
Balance	$ 11,000	$ 62,000
Charge offs	$ 100,000	$ 0
Acquired \| Payment concession
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan		1
Balance		$ 62,000
Acquired \| Real estate
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Real estate \| Retail
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Real estate \| Hotel & motel
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Real estate \| Gas station & car wash
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Real estate \| Mixed use
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	1
Balance	$ 0	$ 62,000
Acquired \| Real estate \| Industrial & warehouse
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Real estate \| Other
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	1	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 93,000	$ 0
Post-Modification	$ 97,000	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Commercial business
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	2	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 649,000	$ 0
Post-Modification	$ 561,000	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	1	0
Balance	$ 11,000	$ 0
Acquired \| Commercial business \| Payment concession
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Balance	$ 11,000
Acquired \| Trade finance
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	0
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 0
Post-Modification	$ 0	$ 0
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Consumer And Other Portfolio Segment [Member]
Troubled Debt Restructuring, By Loan Class, Modified And Subsequent Payment Default
Number of Loans \| loan	0	0
Balance	$ 0	$ 0
Acquired \| Consumer and other
Financing Receivable, Modifications [Line Items]
Number of modified contracts \| loan	0	1
Troubled Debt Restructuring, By Loan Class
Pre-Modification	$ 0	$ 30,000
Post-Modification	$ 0	$ 29,000