Loans Receivable, Net - Credit Quality Indicators for Commercial Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 11,122,696	$ 9,512,810
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	1,496,094
Term loans originated in 2019	1,077,461
Term loans originated in 2018	914,506
Term loans originated in 2017	723,448
Term loans originated in 2016	496,275
Term loans originated in 2015 and prior	1,488,281
Revolving loans	119,830
Total	6,315,895	5,579,307
Commercial Real Estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	1,490,947
Term loans originated in 2019	1,069,503
Term loans originated in 2018	874,673
Term loans originated in 2017	696,371
Term loans originated in 2016	481,392
Term loans originated in 2015 and prior	1,450,596
Revolving loans	116,548
Total	6,180,030
Commercial Real Estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	0
Term loans originated in 2019	0
Term loans originated in 2018	0
Term loans originated in 2017	0
Term loans originated in 2016	0
Term loans originated in 2015 and prior	0
Revolving loans	0
Total	0
Commercial Real Estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	5,147
Term loans originated in 2019	7,958
Term loans originated in 2018	39,833
Term loans originated in 2017	27,077
Term loans originated in 2016	14,883
Term loans originated in 2015 and prior	37,574
Revolving loans	3,282
Total	135,754
Commercial Real Estate | Doubtful/ Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	0
Term loans originated in 2019	0
Term loans originated in 2018	0
Term loans originated in 2017	0
Term loans originated in 2016	0
Term loans originated in 2015 and prior	111
Revolving loans	0
Total	111
Other Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	1,366,664
Term loans originated in 2019	304,430
Term loans originated in 2018	241,222
Term loans originated in 2017	269,857
Term loans originated in 2016	179,225
Term loans originated in 2015 and prior	218,306
Revolving loans	475,113
Total	3,054,817	$ 2,094,254
Other Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	1,341,316
Term loans originated in 2019	284,981
Term loans originated in 2018	234,988
Term loans originated in 2017	264,651
Term loans originated in 2016	177,164
Term loans originated in 2015 and prior	206,431
Revolving loans	467,929
Total	2,977,460
Other Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	19,564
Term loans originated in 2019	12,582
Term loans originated in 2018	0
Term loans originated in 2017	0
Term loans originated in 2016	0
Term loans originated in 2015 and prior	0
Revolving loans	54
Total	32,200
Other Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	5,784
Term loans originated in 2019	6,864
Term loans originated in 2018	6,233
Term loans originated in 2017	5,114
Term loans originated in 2016	2,056
Term loans originated in 2015 and prior	11,329
Revolving loans	7,112
Total	44,492
Other Commercial | Doubtful/ Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	0
Term loans originated in 2019	3
Term loans originated in 2018	1
Term loans originated in 2017	92
Term loans originated in 2016	5
Term loans originated in 2015 and prior	546
Revolving loans	18
Total	$ 665