Past Due Loans, Allowance For Credit Losses, Impaired Loans and TDRS (Details) - Loans and Related Allowance for Credit Losses by Portfolio Segment (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Loans [Abstract]
Total Loans	$ 6,519,079		$ 5,714,360
Allowance for Credit Losses [Abstract]
Total allowance for credit losses	74,722	79,942	87,121	93,214	96,976	102,812
Commercial, Industrial, And Agricultural
Loans [Abstract]
Individually Evaluated for Impairment	18,547		13,178
Collectively Evaluated for Impairment	2,535,395		2,137,440
PCI	1,735		1,722
Total Loans	2,555,677		2,152,340
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	3,599		4,046
Collectively Evaluated for Impairment	27,006		26,335
PCI	0		0
Total allowance for credit losses	30,605		30,381
Office Retail And Industrial
Loans [Abstract]
Individually Evaluated for Impairment	16,140		26,348
Collectively Evaluated for Impairment	1,406,307		1,327,337
PCI	75		0
Total Loans	1,422,522		1,353,685
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		214
Collectively Evaluated for Impairment	9,637		10,191
PCI	0		0
Total allowance for credit losses	9,637		10,405
Multi-Family
Loans [Abstract]
Individually Evaluated for Impairment	1,141		1,296
Collectively Evaluated for Impairment	554,814		331,445
PCI	3,734		132
Total Loans	559,689		332,873
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		18
Collectively Evaluated for Impairment	1,942		1,999
PCI	15		0
Total allowance for credit losses	1,957		2,017
Construction
Loans [Abstract]
Individually Evaluated for Impairment	6,859		5,712
Collectively Evaluated for Impairment	186,586		180,485
PCI	0		0
Total Loans	193,445		186,197
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		178
Collectively Evaluated for Impairment	1,598		6,138
PCI	0		0
Total allowance for credit losses	1,598		6,316
Other Commercial Real Estate
Loans [Abstract]
Individually Evaluated for Impairment	4,719		9,298
Collectively Evaluated for Impairment	860,410		793,703
PCI	6,696		4,070
Total Loans	871,825		807,071
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		704
Collectively Evaluated for Impairment	7,519		10,113
PCI	0		0
Total allowance for credit losses	7,519		10,817
Commercial Real Estate
Loans [Abstract]
Individually Evaluated for Impairment	28,859		42,654
Collectively Evaluated for Impairment	3,008,117		2,632,970
PCI	10,505		4,202
Total Loans	3,047,481		2,679,826
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		1,114
Collectively Evaluated for Impairment	20,696		28,441
PCI	15		0
Total allowance for credit losses	20,711		29,555
Total Corporate Loans
Loans [Abstract]
Individually Evaluated for Impairment	47,406		55,832
Collectively Evaluated for Impairment	5,543,512		4,770,410
PCI	12,240		5,924
Total Loans	5,603,158		4,832,166
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	3,599		5,160
Collectively Evaluated for Impairment	47,702		54,776
PCI	15		0
Total allowance for credit losses	51,316		59,936
Consumer
Loans [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	816,349		738,155
PCI	8,697		9,684
Total Loans	825,046		747,839
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	12,588		13,010
PCI	553		0
Total allowance for credit losses	13,141		13,010
Total Loans Excluding Covered Loans
Loans [Abstract]
Individually Evaluated for Impairment	47,406		55,832
Collectively Evaluated for Impairment	6,359,861		5,508,565
PCI	20,937		15,608
Total Loans	6,428,204		5,580,005
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	3,599		5,160
Collectively Evaluated for Impairment	60,290		67,786
PCI	568		0
Total allowance for credit losses	64,457		72,946
Covered Loans
Loans [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	26,860		30,830
PCI	64,015		103,525
Total Loans	90,875		134,355
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	578		702
PCI	8,071		11,857
Total allowance for credit losses	8,649		12,559
Reserve for Unfunded Commitments
Loans [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	0		0
PCI	0		0
Total Loans	0		0
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	0		0
Collectively Evaluated for Impairment	1,616		1,616
PCI	0		0
Total allowance for credit losses	1,616		1,616
Total Loans Included in Calculation of Allowance
Loans [Abstract]
Individually Evaluated for Impairment	47,406		55,832
Collectively Evaluated for Impairment	6,386,721		5,539,395
PCI	84,952		119,133
Total Loans	6,519,079		5,714,360
Allowance for Credit Losses [Abstract]
Individually Evaluated for Impairment	3,599		5,160
Collectively Evaluated for Impairment	62,484		70,104
PCI	8,639		11,857
Total allowance for credit losses	$ 74,722		$ 87,121