Loans Receivable, Net - Aging of Recorded Investment in Past Due Loans Excluding PCI Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Total loans receivable	$ 8,181,832	$ 7,756,106
Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	21,611	63,780
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	4,949	29,096
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,891	7,558
90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	13,771	27,126
Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	8,160,221	7,692,326
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans receivable	457,674	470,656
Commercial and industrial | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,151	4,005
Commercial and industrial | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,797	3,050
Commercial and industrial | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	0	628
Commercial and industrial | 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	354	327
Commercial and industrial | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	455,523	466,651
Commercial real estate – owner occupied
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,123,973	1,145,065
Commercial real estate – owner occupied | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	7,507	8,886
Commercial real estate – owner occupied | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	515	1,015
Commercial real estate – owner occupied | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	0	0
Commercial real estate – owner occupied | 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	6,992	7,871
Commercial real estate – owner occupied | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,116,466	1,136,179
Commercial real estate – investor
Financing Receivable, Past Due [Line Items]
Total loans receivable	3,922,983	3,491,464
Commercial real estate – investor | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,832	23,252
Commercial real estate – investor | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,074	8,897
Commercial real estate – investor | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	95	3,233
Commercial real estate – investor | 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,663	11,122
Commercial real estate – investor | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	3,920,151	3,468,212
Residential real estate
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,401,240	2,309,459
Residential real estate | Total Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	4,871	22,558
Residential real estate | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	308	15,156
Residential real estate | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,427	3,164
Residential real estate | 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,136	4,238
Residential real estate | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,396,369	2,286,901
Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,677,202	2,648,921
Consumer | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	275,962	339,462
Consumer | Total Past Due | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	4,250	5,079
Consumer | 30-59 Days Past Due | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	1,255	978
Consumer | 60-89 Days Past Due | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	369	533
Consumer | 90 Days or Greater Past Due | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	2,626	3,568
Consumer | Loans Not Past Due | Home Equity Loans And Lines And Other Consumer
Financing Receivable, Past Due [Line Items]
Total loans receivable	$ 271,712	$ 334,383