Allowance for Loan and Lease Losses - Activity (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) segment class	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Allowance for loan and lease losses
Number of primary portfolio segments | segment	3
Allowance for loan and lease losses:
Balance at beginning of period	$ 141,718	$ 137,253	$ 135,494
Charge-offs	(35,987)	(27,573)	(25,925)
Recoveries	10,999	9,858	9,184
Increase (decrease) in Provision	13,800	22,180	18,500
Balance at end of period	130,530	141,718	137,253
Individually evaluated for impairment				$ 203	$ 536	$ 494
Collectively evaluated for impairment				130,327	141,182	136,759
Total allowance for loan and lease losses	$ 141,718	137,253	135,494	130,530	141,718	137,253
Loans and leases:
Individually evaluated for impairment				20,638	30,576	45,349
Collectively evaluated for impairment				13,191,012	13,045,615	12,232,020
Total loans and leases				13,211,650	13,076,191	12,277,369
Commercial Lending
Allowance for loan and lease losses
Number of distinct portfolios | class	4
Commercial and Industrial
Allowance for loan and lease losses:
Balance at beginning of period	$ 34,501	34,006	33,129
Charge-offs	(2,718)	(778)	(1,519)
Recoveries	410	232	844
Increase (decrease) in Provision	(3,218)	1,041	1,552
Balance at end of period	28,975	34,501	34,006
Individually evaluated for impairment				46	108	4
Collectively evaluated for impairment				28,929	34,393	34,002
Total allowance for loan and lease losses	28,975	34,006	34,006	28,975	34,501	34,006
Loans and leases:
Individually evaluated for impairment				4,951	8,719	18,183
Collectively evaluated for impairment				2,738,291	3,200,041	3,117,083
Total loans and leases				2,743,242	3,208,760	3,135,266
Commercial real estate
Allowance for loan and lease losses:
Balance at beginning of period	19,725	18,044	18,448
Recoveries	263	216	596
Increase (decrease) in Provision	2,337	1,465	(1,000)
Balance at end of period	22,325	19,725	18,044
Individually evaluated for impairment				27	32	6
Collectively evaluated for impairment				22,298	19,693	18,038
Total allowance for loan and lease losses	22,325	18,044	18,044	22,325	19,725	18,044
Loans and leases:
Individually evaluated for impairment				723	5,743	10,636
Collectively evaluated for impairment				3,463,230	2,985,040	2,656,961
Total loans and leases				3,463,953	2,990,783	2,667,597
Construction
Allowance for loan and lease losses:
Balance at beginning of period	5,813	6,817	4,513
Increase (decrease) in Provision	(969)	(1,004)	2,304
Balance at end of period	4,844	5,813	6,817
Collectively evaluated for impairment				4,844	5,813	6,817
Total allowance for loan and lease losses	4,844	6,817	4,513	4,844	5,813	6,817
Loans and leases:
Collectively evaluated for impairment				519,241	626,757	632,911
Total loans and leases				519,241	626,757	632,911
Lease financing
Allowance for loan and lease losses:
Balance at beginning of period	432	611	847
Charge-offs	(24)		(147)
Increase (decrease) in Provision	16	(179)	(89)
Balance at end of period	424	432	611
Collectively evaluated for impairment				424	432	611
Total allowance for loan and lease losses	424	611	611	424	432	611
Loans and leases:
Collectively evaluated for impairment				202,483	147,769	165,066
Total loans and leases				202,483	147,769	165,066
Residential
Allowance for loan and lease losses
Specific allocation for impaired loans in which the net collateral value exceeds the unpaid principal balance of the loan				0
Allowance for loan and lease losses:
Balance at beginning of period	44,906	42,852	43,436
Charge-offs	(438)	(165)	(408)
Recoveries	967	940	687
Increase (decrease) in Provision	(6,256)	1,279	(863)
Balance at end of period	39,179	44,906	42,852
Individually evaluated for impairment				130	396	484
Collectively evaluated for impairment				39,049	44,510	42,368
Total allowance for loan and lease losses	39,179	42,852	43,436	39,179	44,906	42,852
Loans and leases:
Individually evaluated for impairment				14,964	16,114	16,530
Collectively evaluated for impairment				4,647,211	4,423,504	4,073,523
Total loans and leases				4,662,175	4,439,618	4,090,053
Consumer
Allowance for loan and lease losses:
Balance at beginning of period	35,813	31,249	28,388
Charge-offs	(32,807)	(26,630)	(23,851)
Recoveries	9,359	8,470	7,057
Increase (decrease) in Provision	22,279	22,724	19,655
Balance at end of period	34,644	35,813	31,249
Collectively evaluated for impairment				34,644	35,813	31,249
Total allowance for loan and lease losses	34,644	31,249	31,249	34,644	35,813	31,249
Loans and leases:
Collectively evaluated for impairment				1,620,556	1,662,504	1,586,476
Total loans and leases				1,620,556	1,662,504	1,586,476
Unallocated
Allowance for loan and lease losses:
Balance at beginning of period	528	3,674	6,733
Increase (decrease) in Provision	(389)	(3,146)	(3,059)
Balance at end of period	139	528	3,674
Collectively evaluated for impairment				139	528	3,674
Total allowance for loan and lease losses	$ 139	$ 3,674	$ 3,674	$ 139	$ 528	$ 3,674