Loans and Allowance for Loan Losses, Past Due (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		$ 26,826	$ 32,700
Current		3,255,179	3,125,632
Total loans		3,282,005	3,158,332
Loans that are 90 days past due and still accruing interest		$ 0	$ 0
Number of days past due		90 days	90 days
30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		$ 3,922	$ 5,737
60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,812	4,620
90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		21,092	22,343
Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		208,794	223,382
Commercial [Member] | Commercial Real Estate [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,899	3,297
Current		183,020	190,827
Total loans		185,919	194,124
Commercial [Member] | Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		109	618
Commercial [Member] | Commercial Real Estate [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	52
Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,790	2,627
Commercial [Member] | Other [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Current		22,875	29,258
Total loans		22,875	29,258
Commercial [Member] | Other [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Commercial [Member] | Other [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Real Estate Mortgage - 1 to 4 Family [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		3,064,281	2,927,356
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		21,296	26,305
Current		2,626,925	2,491,262
Total loans		2,648,221	2,517,567
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		3,254	4,141
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,467	4,157
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		16,575	18,007
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		252	537
Current		59,471	57,118
Total loans		59,723	57,655
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		103	141
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	59
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		149	337
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,190	2,397
Current		354,147	349,737
Total loans		356,337	352,134
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		330	741
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		319	342
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,541	1,314
Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		189	164
Current		8,741	7,430
Total loans		8,930	7,594
Installment [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		126	96
Installment [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		26	10
Installment [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		37	58
New York and Other States [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		24,993	30,085
Current		2,629,158	2,582,294
Total loans	[1]	2,654,151	2,612,379
New York and Other States [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		3,474	4,746
New York and Other States [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,712	4,337
New York and Other States [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		19,807	21,002
New York and Other States [Member] | Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		192,961	203,988
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,899	3,297
Current		167,286	171,491
Total loans	[1]	170,185	174,788
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		109	618
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	52
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,790	2,627
New York and Other States [Member] | Commercial [Member] | Other [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Current		22,776	29,200
Total loans	[1]	22,776	29,200
New York and Other States [Member] | Commercial [Member] | Other [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
New York and Other States [Member] | Commercial [Member] | Other [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
New York and Other States [Member] | Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		19,723	23,996
Current		2,073,710	2,017,144
Total loans	[1]	2,093,433	2,041,140
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,878	3,340
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,467	3,874
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		15,378	16,782
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		252	537
Current		51,600	51,176
Total loans	[1]	51,852	51,713
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		103	141
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	59
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		149	337
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,949	2,108
Current		306,290	306,656
Total loans	[1]	308,239	308,764
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		271	568
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		225	342
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,453	1,198
New York and Other States [Member] | Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		170	147
Current		7,496	6,627
Total loans	[1]	7,666	6,774
New York and Other States [Member] | Installment [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		113	79
New York and Other States [Member] | Installment [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		20	10
New York and Other States [Member] | Installment [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		37	58
Florida [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,833	2,615
Current		626,021	543,338
Total loans		627,854	545,953
Florida [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		448	991
Florida [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		100	283
Florida [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,285	1,341
Florida [Member] | Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		15,833	19,394
Florida [Member] | Commercial [Member] | Commercial Real Estate [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Current		15,734	19,336
Total loans		15,734	19,336
Florida [Member] | Commercial [Member] | Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Commercial [Member] | Commercial Real Estate [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Commercial [Member] | Commercial Real Estate [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Commercial [Member] | Other [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Current		99	58
Total loans		99	58
Florida [Member] | Commercial [Member] | Other [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Commercial [Member] | Other [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,573	2,309
Current		553,215	474,118
Total loans		554,788	476,427
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		376	801
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	283
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,197	1,225
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Current		7,871	5,942
Total loans		7,871	5,942
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		241	289
Current		47,857	43,081
Total loans		48,098	43,370
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		59	173
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		94	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		88	116
Florida [Member] | Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		19	17
Current		1,245	803
Total loans		1,264	820
Florida [Member] | Installment [Member] | 30 to 59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		13	17
Florida [Member] | Installment [Member] | 60 to 89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		6	0
Florida [Member] | Installment [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		$ 0	$ 0

[1] Includes New York, New Jersey, Vermont and Massachusetts.