Loans Receivable - Loan Delinquencies (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loan payment delinquencies
Total delinquency	$ 145,202	$ 119,401
Current	8,691,672	8,689,273
Total loans	8,836,874	8,808,674
90 days or greater delinquent and accruing	31	147
30-59 days delinquent
Loan payment delinquencies
Total delinquency	73,004	48,081
60-89 days delinquent
Loan payment delinquencies
Total delinquency	9,576	19,493
90 days or greater delinquent
Loan payment delinquencies
Total delinquency	62,621	51,827
Personal Banking
Loan payment delinquencies
Total loans	5,382,126	5,336,177
90 days or greater delinquent and accruing	31
Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total loans	2,834,733	2,868,127
90 days or greater delinquent and accruing	0
Personal Banking | Home equity loans
Loan payment delinquencies
Total loans	1,360,654	1,342,918
90 days or greater delinquent and accruing	31
Personal Banking | Consumer finance loans
Loan payment delinquencies
Total loans	936,827
Personal Banking | Consumer loans
Loan payment delinquencies
Total loans	249,912	1,125,132
90 days or greater delinquent and accruing	0
Commercial Banking
Loan payment delinquencies
Total loans	3,454,748	3,472,497
90 days or greater delinquent and accruing	0
Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total loans	2,262,998	2,754,390
90 days or greater delinquent and accruing	0
Commercial Banking | Commercial real estate loans - owner occupied
Loan payment delinquencies
Total loans	487,760
Commercial Banking | Commercial loans
Loan payment delinquencies
Total loans	703,990	718,107
90 days or greater delinquent and accruing	0
Originated
Loan payment delinquencies
Total delinquency		101,108
Current		7,885,949
Total loans		7,987,057
90 days or greater delinquent and accruing		0
Originated | 30-59 days delinquent
Loan payment delinquencies
Total delinquency		41,120
Originated | 60-89 days delinquent
Loan payment delinquencies
Total delinquency		18,613
Originated | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency		41,375
Originated | Personal Banking
Loan payment delinquencies
Total delinquency	79,045	64,521
Current	5,303,081	4,909,329
Total loans	5,382,126	4,973,850
90 days or greater delinquent and accruing	31	0
Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	46,382	37,099
Current	2,788,351	2,748,090
Total loans	2,834,733	2,785,189
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	15,706	11,788
Current	1,344,948	1,088,136
Total loans	1,360,654	1,100,023
90 days or greater delinquent and accruing	31	0
Originated | Personal Banking | Consumer finance loans
Loan payment delinquencies
Total delinquency	11,937
Current	924,890
Total loans	936,827
90 days or greater delinquent and accruing	0
Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	5,020	15,634
Current	244,892	1,073,103
Total loans	249,912	1,088,638
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | 30-59 days delinquent
Loan payment delinquencies
Total delinquency	52,533	34,535
Originated | Personal Banking | 30-59 days delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency	35,322	20,447
Originated | Personal Banking | 30-59 days delinquent | Home equity loans
Loan payment delinquencies
Total delinquency	7,064	5,119
Originated | Personal Banking | 30-59 days delinquent | Consumer finance loans
Loan payment delinquencies
Total delinquency	6,896
Originated | Personal Banking | 30-59 days delinquent | Consumer loans
Loan payment delinquencies
Total delinquency	3,251	8,969
Originated | Personal Banking | 60-89 days delinquent
Loan payment delinquencies
Total delinquency	6,267	10,866
Originated | Personal Banking | 60-89 days delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency	522	5,572
Originated | Personal Banking | 60-89 days delinquent | Home equity loans
Loan payment delinquencies
Total delinquency	2,682	2,096
Originated | Personal Banking | 60-89 days delinquent | Consumer finance loans
Loan payment delinquencies
Total delinquency	2,254
Originated | Personal Banking | 60-89 days delinquent | Consumer loans
Loan payment delinquencies
Total delinquency	809	3,198
Originated | Personal Banking | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency	20,245	19,120
Originated | Personal Banking | 90 days or greater delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency	10,538	11,080
Originated | Personal Banking | 90 days or greater delinquent | Home equity loans
Loan payment delinquencies
Total delinquency	5,960	4,573
Originated | Personal Banking | 90 days or greater delinquent | Consumer finance loans
Loan payment delinquencies
Total delinquency	2,787
Originated | Personal Banking | 90 days or greater delinquent | Consumer loans
Loan payment delinquencies
Total delinquency	960	3,467
Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	66,157	36,587
Current	3,388,591	2,976,620
Total loans	3,454,748	3,013,207
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	31,175	24,944
Current	2,231,823	2,324,104
Total loans	2,262,998	2,349,048
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | Commercial real estate loans - owner occupied
Loan payment delinquencies
Total delinquency	10,259
Current	477,501
Total loans	487,760
Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	24,723	11,643
Current	679,267	652,516
Total loans	703,990	664,159
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | 30-59 days delinquent
Loan payment delinquencies
Total delinquency	20,471	6,585
Originated | Commercial Banking | 30-59 days delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency	10,829	5,598
Originated | Commercial Banking | 30-59 days delinquent | Commercial real estate loans - owner occupied
Loan payment delinquencies
Total delinquency	2,094
Originated | Commercial Banking | 30-59 days delinquent | Commercial loans
Loan payment delinquencies
Total delinquency	7,548	987
Originated | Commercial Banking | 60-89 days delinquent
Loan payment delinquencies
Total delinquency	3,309	7,747
Originated | Commercial Banking | 60-89 days delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency	2,426	1,387
Originated | Commercial Banking | 60-89 days delinquent | Commercial real estate loans - owner occupied
Loan payment delinquencies
Total delinquency	568
Originated | Commercial Banking | 60-89 days delinquent | Commercial loans
Loan payment delinquencies
Total delinquency	315	6,360
Originated | Commercial Banking | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency	42,376	22,255
Originated | Commercial Banking | 90 days or greater delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency	17,919	17,959
Originated | Commercial Banking | 90 days or greater delinquent | Commercial real estate loans - owner occupied
Loan payment delinquencies
Total delinquency	7,597
Originated | Commercial Banking | 90 days or greater delinquent | Commercial loans
Loan payment delinquencies
Total delinquency	$ 16,860	4,296
Acquired
Loan payment delinquencies
Total delinquency		18,293
Current		803,324
Total loans		821,617
90 days or greater delinquent and accruing		147
Acquired | 30-59 days delinquent
Loan payment delinquencies
Total delinquency		6,961
Acquired | 60-89 days delinquent
Loan payment delinquencies
Total delinquency		880
Acquired | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency		10,452
Acquired | Personal Banking
Loan payment delinquencies
Total delinquency		7,926
Current		354,401
Total loans		362,327
90 days or greater delinquent and accruing		147
Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency		4,665
Current		78,273
Total loans		82,938
90 days or greater delinquent and accruing		93
Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency		2,774
Current		240,630
Total loans		243,404
90 days or greater delinquent and accruing		53
Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency		487
Current		35,498
Total loans		35,985
90 days or greater delinquent and accruing		1
Acquired | Personal Banking | 30-59 days delinquent
Loan payment delinquencies
Total delinquency		4,438
Acquired | Personal Banking | 30-59 days delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency		2,849
Acquired | Personal Banking | 30-59 days delinquent | Home equity loans
Loan payment delinquencies
Total delinquency		1,350
Acquired | Personal Banking | 30-59 days delinquent | Consumer loans
Loan payment delinquencies
Total delinquency		239
Acquired | Personal Banking | 60-89 days delinquent
Loan payment delinquencies
Total delinquency		534
Acquired | Personal Banking | 60-89 days delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency		121
Acquired | Personal Banking | 60-89 days delinquent | Home equity loans
Loan payment delinquencies
Total delinquency		309
Acquired | Personal Banking | 60-89 days delinquent | Consumer loans
Loan payment delinquencies
Total delinquency		104
Acquired | Personal Banking | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency		2,954
Acquired | Personal Banking | 90 days or greater delinquent | Residential mortgage loans
Loan payment delinquencies
Total delinquency		1,695
Acquired | Personal Banking | 90 days or greater delinquent | Home equity loans
Loan payment delinquencies
Total delinquency		1,115
Acquired | Personal Banking | 90 days or greater delinquent | Consumer loans
Loan payment delinquencies
Total delinquency		144
Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency		10,367
Current		448,923
Total loans		459,290
90 days or greater delinquent and accruing		0
Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency		9,681
Current		395,661
Total loans		405,342
90 days or greater delinquent and accruing		0
Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency		686
Current		53,262
Total loans		53,948
90 days or greater delinquent and accruing		0
Acquired | Commercial Banking | 30-59 days delinquent
Loan payment delinquencies
Total delinquency		2,523
Acquired | Commercial Banking | 30-59 days delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency		2,323
Acquired | Commercial Banking | 30-59 days delinquent | Commercial loans
Loan payment delinquencies
Total delinquency		200
Acquired | Commercial Banking | 60-89 days delinquent
Loan payment delinquencies
Total delinquency		346
Acquired | Commercial Banking | 60-89 days delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency		303
Acquired | Commercial Banking | 60-89 days delinquent | Commercial loans
Loan payment delinquencies
Total delinquency		43
Acquired | Commercial Banking | 90 days or greater delinquent
Loan payment delinquencies
Total delinquency		7,498
Acquired | Commercial Banking | 90 days or greater delinquent | Commercial real estate loans
Loan payment delinquencies
Total delinquency		7,055
Acquired | Commercial Banking | 90 days or greater delinquent | Commercial loans
Loan payment delinquencies
Total delinquency		$ 443