Loans (Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade) (Details) $ in Thousands		Jun. 30, 2017 USD ($) grade	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) grade	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Allowance		$ 197,257	$ 201,968	$ 202,068	$ 199,807	$ 204,034	$ 210,242
Total loans collectively evaluated for impairment		19,697,240			18,248,021
Total loans individually evaluated for impairment		265,330			319,322
Purchase credit impaired loans - recorded investment		26,749			21,994
Allowance - collectively evaluated for impairment		153,742			146,829
Allowance - individually evaluated for impairment		42,985			52,151
Allowance - purchased credit impaired loans		$ 530		$ 700	$ 827
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of total commercial loans (percent)		100.00%		100.00%
Loans and Leases Receivable, Allowance		$ 122,849		$ 123,250
Total loans collectively evaluated for impairment		14,743,860		14,187,074
Total loans individually evaluated for impairment		41,058		51,086
Purchase credit impaired loans - recorded investment		25,297		45,450
Total commercial loans		14,810,215		14,283,610
Allowance - collectively evaluated for impairment		118,886		118,518
Allowance - individually evaluated for impairment		3,817		4,413
Allowance - purchased credit impaired loans		$ 146		$ 319
Percent of loan collectively evaluated for impairment (percent)		99.00%		99.00%
Percent of loan individually evaluated for impairment (percent)		1.00%		1.00%
Percent of loan purchased-credit impaired (percent)		0.00%		0.00%
General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		$ 10,141,915		$ 9,710,168
Total loans individually evaluated for impairment		34,897		44,753
Purchase credit impaired loans - recorded investment		21,272		40,532
Total commercial loans		10,198,084		9,795,453
Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		2,092,762		2,045,189
Total loans individually evaluated for impairment		0		0
Purchase credit impaired loans - recorded investment		0		0
Total commercial loans		2,092,762		2,045,189
TRUPs
Accounts, Notes, Loans and Financing Receivable [Line Items]
Valuation allowance		25,500		25,500
TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment	[1]	304,236		304,236
Total loans individually evaluated for impairment	[1]	3,137		3,209
Purchase credit impaired loans - recorded investment	[1]	0		0
Total commercial loans	[1]	307,373		307,445
Valuation allowance		$ 25,500		$ 25,500
Highest internal grade | grade		13		13
Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		$ 2,168,989		$ 2,085,619
Total loans individually evaluated for impairment		1,731		1,831
Purchase credit impaired loans - recorded investment		3,974		4,583
Total commercial loans		2,174,694		2,092,033
Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans collectively evaluated for impairment		35,958		41,862
Total loans individually evaluated for impairment		1,293		1,293
Purchase credit impaired loans - recorded investment		51		335
Total commercial loans		37,302		43,490
Commercial Loan P D Grade One | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 600,454		$ 466,257
Percent of total commercial loans (percent)		4.00%		3.00%
Loans and Leases Receivable, Allowance		$ 93		$ 77
Commercial Loan P D Grade One | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		599,112		465,179
Commercial Loan P D Grade One | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade One | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade One | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,342		1,078
Commercial Loan P D Grade One | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Two | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 923,676		$ 803,012
Percent of total commercial loans (percent)		6.00%		6.00%
Loans and Leases Receivable, Allowance		$ 432		$ 403
Commercial Loan P D Grade Two | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		912,224		791,183
Commercial Loan P D Grade Two | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Two | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Two | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		11,375		11,742
Commercial Loan P D Grade Two | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		77		87
Commercial Loan P D Grade Three | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,252,270		$ 1,107,542
Percent of total commercial loans (percent)		8.00%		8.00%
Loans and Leases Receivable, Allowance		$ 294		$ 304
Commercial Loan P D Grade Three | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		482,603		491,386
Commercial Loan P D Grade Three | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		615,227		462,486
Commercial Loan P D Grade Three | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Three | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		154,399		153,670
Commercial Loan P D Grade Three | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		41		0
Commercial Loan P D Grade Four | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,658,529		$ 1,532,811
Percent of total commercial loans (percent)		11.00%		11.00%
Loans and Leases Receivable, Allowance		$ 941		$ 953
Commercial Loan P D Grade Four | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		952,746		978,282
Commercial Loan P D Grade Four | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		455,459		332,107
Commercial Loan P D Grade Four | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Four | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		250,107		222,422
Commercial Loan P D Grade Four | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		217		0
Commercial Loan P D Grade Five | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 2,103,528		$ 1,873,965
Percent of total commercial loans (percent)		14.00%		13.00%
Loans and Leases Receivable, Allowance		$ 8,023		$ 6,670
Commercial Loan P D Grade Five | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,431,131		1,232,401
Commercial Loan P D Grade Five | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		209,681		275,209
Commercial Loan P D Grade Five | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Five | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		462,468		365,653
Commercial Loan P D Grade Five | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		248		702
Commercial Loan P D Grade Six | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 2,438,647		$ 2,502,310
Percent of total commercial loans (percent)		17.00%		17.00%
Loans and Leases Receivable, Allowance		$ 10,258		$ 10,403
Commercial Loan P D Grade Six | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,575,587		1,540,519
Commercial Loan P D Grade Six | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		464,550		614,109
Commercial Loan P D Grade Six | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Six | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		392,030		338,344
Commercial Loan P D Grade Six | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		6,480		9,338
Commercial Loan P D Grade Seven | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 2,144,768		$ 2,228,369
Percent of total commercial loans (percent)		15.00%		16.00%
Loans and Leases Receivable, Allowance		$ 13,480		$ 14,010
Commercial Loan P D Grade Seven | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,559,070		1,556,117
Commercial Loan P D Grade Seven | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		170,351		317,283
Commercial Loan P D Grade Seven | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Seven | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		412,035		352,390
Commercial Loan P D Grade Seven | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		3,312		2,579
Commercial Loan P D Grade Eight | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 1,455,413		$ 1,422,786
Percent of total commercial loans (percent)		10.00%		10.00%
Loans and Leases Receivable, Allowance		$ 23,210		$ 25,986
Commercial Loan P D Grade Eight | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		1,061,919		963,359
Commercial Loan P D Grade Eight | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		89,754		30,974
Commercial Loan P D Grade Eight | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Eight | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		298,308		425,503
Commercial Loan P D Grade Eight | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		5,432		2,950
Commercial Loan P D Grade Nine | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 626,010		$ 725,767
Percent of total commercial loans (percent)		4.00%		5.00%
Loans and Leases Receivable, Allowance		$ 10,802		$ 13,857
Commercial Loan P D Grade Nine | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		491,733		611,774
Commercial Loan P D Grade Nine | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		62,426		4,299
Commercial Loan P D Grade Nine | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Nine | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		66,838		105,277
Commercial Loan P D Grade Nine | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		5,013		4,417
Commercial Loan P D Grade Ten | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 422,893		$ 423,616
Percent of total commercial loans (percent)		3.00%		3.00%
Loans and Leases Receivable, Allowance		$ 9,243		$ 8,400
Commercial Loan P D Grade Ten | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		363,620		355,359
Commercial Loan P D Grade Ten | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		3,583		8,663
Commercial Loan P D Grade Ten | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Ten | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		47,567		50,484
Commercial Loan P D Grade Ten | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		8,123		9,110
Commercial Loan P D Grade Eleven | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 262,076		$ 265,371
Percent of total commercial loans (percent)		2.00%		2.00%
Loans and Leases Receivable, Allowance		$ 7,522		$ 6,556
Commercial Loan P D Grade Eleven | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		214,592		238,230
Commercial Loan P D Grade Eleven | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Eleven | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Eleven | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		44,301		20,600
Commercial Loan P D Grade Eleven | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		3,183		6,541
Commercial Loan P D Grade Twelve | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 217,643		$ 190,094
Percent of total commercial loans (percent)		1.00%		1.00%
Loans and Leases Receivable, Allowance		$ 7,684		$ 6,377
Commercial Loan P D Grade Twelve | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		180,210		170,531
Commercial Loan P D Grade Twelve | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		21,691		0
Commercial Loan P D Grade Twelve | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	0		0
Commercial Loan P D Grade Twelve | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		13,000		15,395
Commercial Loan P D Grade Twelve | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		2,742		4,168
Commercial Loan P D Grade Thirteen | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 418,059		$ 432,571
Percent of total commercial loans (percent)		3.00%		3.00%
Loans and Leases Receivable, Allowance		$ 3,821		$ 4,225
Commercial Loan P D Grade Thirteen | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		107,024		121,276
Commercial Loan P D Grade Thirteen | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		0		0
Commercial Loan P D Grade Thirteen | TRUPs | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade	[1]	304,236		304,236
Commercial Loan P D Grade Thirteen | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		6,688		6,748
Commercial Loan P D Grade Thirteen | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		111		311
Commercial Loan P D Grade Fourteen Fifteen Sixteen | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 219,894		$ 212,603
Percent of total commercial loans (percent)		1.00%		1.00%
Loans and Leases Receivable, Allowance		$ 23,083		$ 20,297
Commercial Loan P D Grade Fourteen Fifteen Sixteen | General C I | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		210,344		194,572
Commercial Loan P D Grade Fourteen Fifteen Sixteen | Loans To Mortgage Companies [Member] | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		40		59
Commercial Loan P D Grade Fourteen Fifteen Sixteen | TRUPs | Commercial Portfolio Segment
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 | Income C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		8,531		16,313
Commercial Loan P D Grade Fourteen Fifteen Sixteen | Residential C R E | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan, Disaggregated by PD grade		$ 979		$ 1,659

[1] Balances as of June 30, 2017 and December 31, 2016, presented net of a $25.5 million valuation allowance. Based on the underlying structure of the notes, the highest possible internal grade is “13”.