Loans Receivable, Net - Credit Quality Indicators for Commercial Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Credit Quality Indicators By Origination
Total	$ 11,293,891	$ 11,122,696
Commercial real estate
Credit Quality Indicators By Origination
Term loans originated current fiscal year	1,665,923	1,496,094
Term loans originated fiscal year before current fiscal year	1,310,854	1,077,461
Term loans originated two years before current fiscal year	883,727	914,506
Term loans originated three years before current fiscal year	748,629	723,448
Term loans originated four years before current fiscal year	558,997	496,275
Term loans originated five years before current fiscal year	1,598,606	1,488,281
Revolving loans	145,833	119,830
Total	6,912,569	6,315,895
Commercial real estate | Pass
Credit Quality Indicators By Origination
Term loans originated current fiscal year	1,664,908	1,490,947
Term loans originated fiscal year before current fiscal year	1,306,097	1,069,503
Term loans originated two years before current fiscal year	872,635	874,673
Term loans originated three years before current fiscal year	695,068	696,371
Term loans originated four years before current fiscal year	531,073	481,392
Term loans originated five years before current fiscal year	1,547,558	1,450,596
Revolving loans	142,781	116,548
Total	6,760,120	6,180,030
Commercial real estate | Special Mention
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0	0
Term loans originated fiscal year before current fiscal year	0	0
Term loans originated two years before current fiscal year	0	0
Term loans originated three years before current fiscal year	0	0
Term loans originated four years before current fiscal year	0	0
Term loans originated five years before current fiscal year	0	0
Revolving loans	0	0
Total	0	0
Commercial real estate | Substandard
Credit Quality Indicators By Origination
Term loans originated current fiscal year	1,015	5,147
Term loans originated fiscal year before current fiscal year	4,757	7,958
Term loans originated two years before current fiscal year	11,092	39,833
Term loans originated three years before current fiscal year	53,561	27,077
Term loans originated four years before current fiscal year	27,924	14,883
Term loans originated five years before current fiscal year	51,023	37,574
Revolving loans	3,051	3,282
Total	152,423	135,754
Commercial real estate | Doubtful/ Loss
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0	0
Term loans originated fiscal year before current fiscal year	0	0
Term loans originated two years before current fiscal year	0	0
Term loans originated three years before current fiscal year	0	0
Term loans originated four years before current fiscal year	0	0
Term loans originated five years before current fiscal year	25	111
Revolving loans	1	0
Total	26	111
Other commercial
Credit Quality Indicators By Origination
Term loans originated current fiscal year	694,243	1,366,664
Term loans originated fiscal year before current fiscal year	477,065	304,430
Term loans originated two years before current fiscal year	239,843	241,222
Term loans originated three years before current fiscal year	184,542	269,857
Term loans originated four years before current fiscal year	215,294	179,225
Term loans originated five years before current fiscal year	314,426	218,306
Revolving loans	473,203	475,113
Total	2,598,616	3,054,817
Other commercial | Pass
Credit Quality Indicators By Origination
Term loans originated current fiscal year	690,542	1,341,316
Term loans originated fiscal year before current fiscal year	461,088	284,981
Term loans originated two years before current fiscal year	230,852	234,988
Term loans originated three years before current fiscal year	178,564	264,651
Term loans originated four years before current fiscal year	214,143	177,164
Term loans originated five years before current fiscal year	300,084	206,431
Revolving loans	443,561	467,929
Total	2,518,834	2,977,460
Other commercial | Special Mention
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0	19,564
Term loans originated fiscal year before current fiscal year	0	12,582
Term loans originated two years before current fiscal year	0	0
Term loans originated three years before current fiscal year	0	0
Term loans originated four years before current fiscal year	0	0
Term loans originated five years before current fiscal year	0	0
Revolving loans	0	54
Total	0	32,200
Other commercial | Substandard
Credit Quality Indicators By Origination
Term loans originated current fiscal year	3,701	5,784
Term loans originated fiscal year before current fiscal year	15,976	6,864
Term loans originated two years before current fiscal year	8,988	6,233
Term loans originated three years before current fiscal year	5,977	5,114
Term loans originated four years before current fiscal year	1,148	2,056
Term loans originated five years before current fiscal year	13,792	11,329
Revolving loans	29,626	7,112
Total	79,208	44,492
Other commercial | Doubtful/ Loss
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0	0
Term loans originated fiscal year before current fiscal year	1	3
Term loans originated two years before current fiscal year	3	1
Term loans originated three years before current fiscal year	1	92
Term loans originated four years before current fiscal year	3	5
Term loans originated five years before current fiscal year	550	546
Revolving loans	16	18
Total	$ 574	$ 665