Loans (Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade) (Details)		Mar. 31, 2016 USD ($) number	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($) number	Dec. 31, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 204,034,000	$ 210,242,000	$ 228,328,000	$ 232,448,000
Total loans collectively evaluated for impairment		17,231,978,000		16,351,273,000
Total loans individually evaluated for impairment		312,762,000		348,158,000
Allowance - collectively evaluated for impairment		145,010,000		158,872,000
Allowance - individually evaluated for impairment		57,876,000		66,361,000
Allowance - purchased credit impaired loans		1,148,000		3,095,000
Purchase credit impaired loans - recorded investment		30,254,000		32,692,000
General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		8,381,292,000		7,613,746,000
Total loans individually evaluated for impairment		41,158,000		39,882,000
Total commercial loans		8,435,491,000		7,658,486,000
Purchase credit impaired loans - recorded investment		13,041,000		4,858,000
Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		1,495,858,000		1,641,672,000
Total loans individually evaluated for impairment		0		0
Total commercial loans		1,495,858,000		1,641,672,000
Purchase credit impaired loans - recorded investment		0		0
TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment	[1]	304,527,000		325,382,000
Total loans individually evaluated for impairment	[1]	3,307,000		12,815,000
Total commercial loans	[1]	307,834,000		338,197,000
LOCOM valuation allowance		$ 25,500,000		$ 26,200,000
Highest internal grade | number		13		13
Purchase credit impaired loans - recorded investment		$ 0		$ 0
Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		1,762,049,000		1,252,912,000
Total loans individually evaluated for impairment		7,574,000		10,904,000
Total commercial loans		1,779,493,000		1,287,512,000
Purchase credit impaired loans - recorded investment		9,870,000		23,696,000
Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		64,628,000		30,032,000
Total loans individually evaluated for impairment		1,376,000		1,624,000
Total commercial loans		69,076,000		33,385,000
Purchase credit impaired loans - recorded investment		$ 3,072,000		$ 1,729,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of total commercial loans		100.00%		100.00%
Allowance for loan losses		$ 106,513,000		$ 85,317,000
Total loans collectively evaluated for impairment		12,008,354,000		10,863,744,000
Total loans individually evaluated for impairment		53,415,000		65,225,000
Total commercial loans		12,087,752,000		10,959,252,000
Allowance - collectively evaluated for impairment		96,455,000		76,082,000
Allowance - individually evaluated for impairment		9,636,000		6,630,000
Allowance - purchased credit impaired loans		$ 422,000		$ 2,605,000
Percent of loan collectively evaluated for impairment		99.00%		99.00%
Percent of loan individually evaluated for impairment		1.00%		1.00%
Purchase credit impaired loans - recorded investment		$ 25,983,000		$ 30,283,000
Percent of loan purchased-credit impaired		0.00%		0.00%
Commercial Loan P D Grade One [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 595,686,000		$ 447,389,000
Percent of total commercial loans		5.00%		4.00%
Allowance for loan losses		$ 127,000		$ 75,000
Commercial Loan P D Grade One [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		595,106,000		446,725,000
Commercial Loan P D Grade One [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade One [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade One [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		580,000		605,000
Commercial Loan P D Grade One [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		59,000
Commercial Loan P D Grade Two [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 618,079,000		$ 552,198,000
Percent of total commercial loans		5.00%		5.00%
Allowance for loan losses		$ 324,000		$ 173,000
Commercial Loan P D Grade Two [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		607,670,000		550,069,000
Commercial Loan P D Grade Two [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Two [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Two [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		10,292,000		1,896,000
Commercial Loan P D Grade Two [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		117,000		233,000
Commercial Loan P D Grade Three [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,062,481,000		$ 868,373,000
Percent of total commercial loans		9.00%		8.00%
Allowance for loan losses		$ 329,000		$ 228,000
Commercial Loan P D Grade Three [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		516,275,000		528,347,000
Commercial Loan P D Grade Three [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		379,810,000		276,653,000
Commercial Loan P D Grade Three [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Three [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		166,396,000		63,112,000
Commercial Loan P D Grade Three [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		261,000
Commercial Loan P D Grade Four [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,492,283,000		$ 962,896,000
Percent of total commercial loans		12.00%		9.00%
Allowance for loan losses		$ 987,000		$ 435,000
Commercial Loan P D Grade Four [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		936,719,000		663,213,000
Commercial Loan P D Grade Four [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		366,958,000		235,434,000
Commercial Loan P D Grade Four [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Four [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		180,323,000		64,020,000
Commercial Loan P D Grade Four [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		8,283,000		229,000
Commercial Loan P D Grade Five [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,575,936,000		$ 1,690,716,000
Percent of total commercial loans		13.00%		15.00%
Allowance for loan losses		$ 6,184,000		$ 2,743,000
Commercial Loan P D Grade Five [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,078,567,000		1,050,800,000
Commercial Loan P D Grade Five [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		252,228,000		384,418,000
Commercial Loan P D Grade Five [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Five [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		241,553,000		253,658,000
Commercial Loan P D Grade Five [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		3,588,000		1,840,000
Commercial Loan P D Grade Six [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,884,003,000		$ 1,828,941,000
Percent of total commercial loans		16.00%		17.00%
Allowance for loan losses		$ 9,711,000		$ 5,488,000
Commercial Loan P D Grade Six [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,195,082,000		1,111,069,000
Commercial Loan P D Grade Six [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		350,253,000		498,752,000
Commercial Loan P D Grade Six [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Six [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		326,060,000		213,787,000
Commercial Loan P D Grade Six [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		12,608,000		5,333,000
Commercial Loan P D Grade Seven [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,912,480,000		$ 1,716,146,000
Percent of total commercial loans		15.00%		16.00%
Allowance for loan losses		$ 12,953,000		$ 9,169,000
Commercial Loan P D Grade Seven [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,370,338,000		1,278,125,000
Commercial Loan P D Grade Seven [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		108,550,000		192,154,000
Commercial Loan P D Grade Seven [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Seven [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		421,650,000		231,551,000
Commercial Loan P D Grade Seven [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		11,942,000		14,316,000
Commercial Loan P D Grade Eight [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,026,025,000		$ 937,770,000
Percent of total commercial loans		8.00%		9.00%
Allowance for loan losses		$ 16,815,000		$ 9,786,000
Commercial Loan P D Grade Eight [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		771,016,000		735,695,000
Commercial Loan P D Grade Eight [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		38,059,000		27,813,000
Commercial Loan P D Grade Eight [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Eight [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		215,048,000		173,744,000
Commercial Loan P D Grade Eight [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,902,000		518,000
Commercial Loan P D Grade Nine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 569,095,000		$ 634,175,000
Percent of total commercial loans		5.00%		6.00%
Allowance for loan losses		$ 10,571,000		$ 8,642,000
Commercial Loan P D Grade Nine [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		502,867,000		474,912,000
Commercial Loan P D Grade Nine [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		26,448,000
Commercial Loan P D Grade Nine [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Nine [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		64,420,000		131,893,000
Commercial Loan P D Grade Nine [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,808,000		922,000
Commercial Loan P D Grade Ten [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 333,688,000		$ 254,982,000
Percent of total commercial loans		3.00%		2.00%
Allowance for loan losses		$ 5,286,000		$ 4,811,000
Commercial Loan P D Grade Ten [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		249,608,000		228,176,000
Commercial Loan P D Grade Ten [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Ten [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Ten [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		67,575,000		26,641,000
Commercial Loan P D Grade Ten [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		16,505,000		165,000
Commercial Loan P D Grade Eleven [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 189,324,000		$ 237,840,000
Percent of total commercial loans		2.00%		2.00%
Allowance for loan losses		$ 4,895,000		$ 5,783,000
Commercial Loan P D Grade Eleven [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		168,079,000		209,639,000
Commercial Loan P D Grade Eleven [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Eleven [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Eleven [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		18,479,000		27,255,000
Commercial Loan P D Grade Eleven [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		2,766,000		946,000
Commercial Loan P D Grade Twelve [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 120,715,000		$ 122,753,000
Percent of total commercial loans		1.00%		1.00%
Allowance for loan losses		$ 3,588,000		$ 4,103,000
Commercial Loan P D Grade Twelve [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		96,442,000		93,055,000
Commercial Loan P D Grade Twelve [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Twelve [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Twelve [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		20,685,000		29,205,000
Commercial Loan P D Grade Twelve [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		3,588,000		493,000
Commercial Loan P D Grade Thirteen [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 421,507,000		$ 445,763,000
Percent of total commercial loans		3.00%		4.00%
Allowance for loan losses		$ 4,056,000		$ 4,989,000
Commercial Loan P D Grade Thirteen [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		108,610,000		114,775,000
Commercial Loan P D Grade Thirteen [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Thirteen [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	304,527,000		325,382,000
Commercial Loan P D Grade Thirteen [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		7,756,000		4,530,000
Commercial Loan P D Grade Thirteen [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		614,000		1,076,000
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 207,052,000		$ 163,802,000
Percent of total commercial loans		2.00%		1.00%
Allowance for loan losses		$ 20,629,000		$ 19,657,000
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member] | General C I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		184,913,000		129,146,000
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member] | Loans To Mortgage Companies [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member] | TRUPs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member] | Income C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		21,232,000		31,015,000
Commercial Loan P D Grade Fourteen Fifteen Sixteen [Member] | Residential C R E [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 907,000		$ 3,641,000

[1] Balances as of March 31 , 2016 and 2015 , presented net of $ 25.5 million and $ 26.2 million, respectively, in lower of cost or market (“LOCOM”) valuation allowance. Based on the underlying structure of the notes, the highest possible internal grade is " 13 ".