Loans and Allowance for Loan Losses, Past Due (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		$ 21,522	$ 27,065
Current		3,427,414	3,403,521
Total loans		3,448,936	3,430,586
Loans that are 90 days past due and still accruing interest		$ 0	$ 0
Number of days past due		90 days	90 days
30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		$ 5,029	$ 9,189
60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,805	3,188
90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		14,688	14,688
Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		184,451	191,194
Commercial [Member] | Commercial Real Estate [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,896	1,799
Current		160,162	161,810
Total loans		162,058	163,609
Commercial [Member] | Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		270	50
Commercial [Member] | Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	43
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		1,626	1,706
Commercial [Member] | Other [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		100	0
Current		22,293	27,585
Total loans		22,393	27,585
Commercial [Member] | Other [Member] | 30-59 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] | 60-89 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		100	0
Real Estate Mortgage - 1 to 4 Family [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		3,256,208	3,230,574
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		16,992	22,212
Current		2,839,405	2,801,875
Total loans		2,856,397	2,824,087
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		4,270	8,321
Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,578	2,993
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		11,144	10,898
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		40	146
Current		73,491	71,500
Total loans		73,531	71,646
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		5	69
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		13	3
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		22	74
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		2,425	2,791
Current		323,855	332,050
Total loans		326,280	334,841
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		452	685
Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		199	111
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		1,774	1,995
Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		69	117
Current		8,208	8,701
Total loans		8,277	8,818
Installment [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		32	64
Installment [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		15	38
Installment [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		22	15
New York and Other States [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		18,713	23,588
Current		2,670,335	2,668,747
Total loans	[1]	2,689,048	2,692,335
New York and Other States [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		3,311	7,198
New York and Other States [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,375	3,113
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		14,027	13,277
New York and Other States [Member] | Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		172,731	178,905
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		1,896	1,799
Current		148,787	149,567
Total loans	[1]	150,683	151,366
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		270	50
New York and Other States [Member] | Commercial [Member] | Commercial Real Estate [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	43
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		1,626	1,706
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		100	0
Current		21,948	27,539
Total loans	[1]	22,048	27,539
New York and Other States [Member] | Commercial [Member] | Other [Member] | 30-59 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] | 60-89 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		100	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		14,372	18,946
Current		2,153,599	2,139,958
Total loans	[1]	2,167,971	2,158,904
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,614	6,379
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,185	2,924
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		10,573	9,643
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		30	127
Current		61,883	60,765
Total loans	[1]	61,913	60,892
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		5	50
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		3	3
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		22	74
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		2,265	2,635
Current		277,721	283,951
Total loans	[1]	279,986	286,586
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		402	685
New York and Other States [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		179	111
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		1,684	1,839
New York and Other States [Member] | Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		50	81
Current		6,397	6,967
Total loans	[1]	6,447	7,048
New York and Other States [Member] | Installment [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		20	34
New York and Other States [Member] | Installment [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		8	32
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		22	15
Florida [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		2,809	3,477
Current		757,079	734,774
Total loans		759,888	738,251
Florida [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,718	1,991
Florida [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		430	75
Florida [Member] | 90+ Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		661	1,411
Florida [Member] | Commercial [Member]
Aging of the recorded investment in past due loans [Abstract]
Total loans		11,720	12,289
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		11,375	12,243
Total loans		11,375	12,243
Florida [Member] | Commercial [Member] | Commercial Real Estate [Member] | 30-59 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] | 60-89 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		345	46
Total loans		345	46
Florida [Member] | Commercial [Member] | Other [Member] | 30-59 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] | 60-89 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		2,620	3,266
Current		685,806	661,917
Total loans		688,426	665,183
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		1,656	1,942
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | First Mortgages [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		393	69
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		571	1,255
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		10	19
Current		11,608	10,735
Total loans		11,618	10,754
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		0	19
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Loans [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		10	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		160	156
Current		46,134	48,099
Total loans		46,294	48,255
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		50	0
Florida [Member] | Real Estate Mortgage - 1 to 4 Family [Member] | Home Equity Lines of Credit [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		20	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		90	156
Florida [Member] | Installment [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		19	36
Current		1,811	1,734
Total loans		1,830	1,770
Florida [Member] | Installment [Member] | 30-59 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		12	30
Florida [Member] | Installment [Member] | 60-89 Days Past Due [Member]
Aging of the recorded investment in past due loans [Abstract]
Total 30+ days Past Due		7	6
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.