Allowance for Credit Losses - Activity (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Allowance for loan and lease losses:
Balance at beginning of period	$ 130,530	$ 141,718
Adoption of ASU 2016-13			$ 770
Charge-offs	(8,806)	(8,622)
Recoveries	2,670	2,770
Increase (decrease) in Provision	40,849	5,680
Balance at end of period	166,013	141,546
Commercial and Industrial
Allowance for loan and lease losses:
Balance at beginning of period	28,975	34,501
Adoption of ASU 2016-13			(16,105)
Charge-offs	(201)
Recoveries	220	37
Increase (decrease) in Provision	7,995	(2,745)
Balance at end of period	20,884	31,793
Commercial real estate
Allowance for loan and lease losses:
Balance at beginning of period	22,325	19,725
Adoption of ASU 2016-13			10,559
Recoveries		31
Increase (decrease) in Provision	9,954	1,441
Balance at end of period	42,838	21,197
Construction
Allowance for loan and lease losses:
Balance at beginning of period	4,844	5,813
Adoption of ASU 2016-13			(1,803)
Recoveries	110
Increase (decrease) in Provision	5,673	(432)
Balance at end of period	8,824	5,381
Lease financing
Allowance for loan and lease losses:
Balance at beginning of period	424	432
Adoption of ASU 2016-13			207
Charge-offs		(24)
Increase (decrease) in Provision	220	3
Balance at end of period	851	411
Residential
Allowance for loan and lease losses:
Balance at beginning of period	39,179
Consumer
Allowance for loan and lease losses:
Balance at beginning of period	34,644	35,813
Adoption of ASU 2016-13			15,575
Charge-offs	(8,597)	(8,598)
Recoveries	2,083	2,452
Increase (decrease) in Provision	12,334	5,432
Balance at end of period	56,039	35,099
Unallocated
Allowance for loan and lease losses:
Balance at beginning of period	139	528
Adoption of ASU 2016-13			(139)
Increase (decrease) in Provision		2,226
Balance at end of period		2,754
Residential mortgage \| Residential
Allowance for loan and lease losses:
Balance at beginning of period	29,303	44,906
Adoption of ASU 2016-13			(2,793)
Recoveries	135	250
Increase (decrease) in Provision	3,376	(245)
Balance at end of period	30,021	$ 44,911
Home equity \| Residential
Allowance for loan and lease losses:
Balance at beginning of period	9,876
Adoption of ASU 2016-13			$ (4,731)
Charge-offs	(8)
Recoveries	122
Increase (decrease) in Provision	1,297
Balance at end of period	$ 6,556

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of increase (decrease) of allowance reserve for credit loss.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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