Notes Receivable, Net - Credit Quality Indicators for RRE and Consumer 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
Residential Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	208,679
Term loans originated in 2019	181,924
Term loans originated in 2018	100,273
Term loans originated in 2017	76,394
Term loans originated in 2016	53,819
Term loans originated in 2015 and prior	179,085
Revolving loans	2,334
Total	802,508	926,388
Residential Real Estate | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	207,432
Term loans originated in 2019	179,915
Term loans originated in 2018	99,135
Term loans originated in 2017	75,527
Term loans originated in 2016	52,905
Term loans originated in 2015 and prior	174,281
Revolving loans	2,334
Total	791,529
Residential Real Estate | 30-89 Days Past Due
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	1,247
Term loans originated in 2019	2,009
Term loans originated in 2018	556
Term loans originated in 2017	867
Term loans originated in 2016	87
Term loans originated in 2015 and prior	1,876
Revolving loans	0
Total	6,642
Residential Real Estate | Non-Accrual and 90 Days or More Past Due
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	0
Term loans originated in 2019	0
Term loans originated in 2018	582
Term loans originated in 2017	0
Term loans originated in 2016	827
Term loans originated in 2015 and prior	2,928
Revolving loans	0
Total	4,337
Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	89
Term loans originated in 2019	807
Term loans originated in 2018	1,782
Term loans originated in 2017	1,452
Term loans originated in 2016	1,016
Term loans originated in 2015 and prior	14,025
Revolving loans	617,234
Total	636,405	617,201
Home Equity | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	89
Term loans originated in 2019	771
Term loans originated in 2018	1,782
Term loans originated in 2017	1,426
Term loans originated in 2016	1,016
Term loans originated in 2015 and prior	13,042
Revolving loans	612,545
Total	630,671
Home Equity | 30-89 Days Past Due
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	26
Term loans originated in 2016	0
Term loans originated in 2015 and prior	463
Revolving loans	2,397
Total	2,886
Home Equity | Non-Accrual and 90 Days or More Past Due
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	0
Term loans originated in 2019	36
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	520
Revolving loans	2,292
Total	2,848
Consumer and Other
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	131,302
Term loans originated in 2019	66,327
Term loans originated in 2018	42,827
Term loans originated in 2017	16,287
Term loans originated in 2016	10,519
Term loans originated in 2015 and prior	18,692
Revolving loans	27,117
Total	313,071	$ 295,660
Consumer and Other | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	131,098
Term loans originated in 2019	65,921
Term loans originated in 2018	42,557
Term loans originated in 2017	16,202
Term loans originated in 2016	10,409
Term loans originated in 2015 and prior	17,334
Revolving loans	26,704
Total	310,225
Consumer and Other | 30-89 Days Past Due
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	158
Term loans originated in 2019	170
Term loans originated in 2018	212
Term loans originated in 2017	38
Term loans originated in 2016	48
Term loans originated in 2015 and prior	1,155
Revolving loans	411
Total	2,192
Consumer and Other | Non-Accrual and 90 Days or More Past Due
Financing Receivable, Credit Quality Indicator [Line Items]
Term loans originated in 2020	46
Term loans originated in 2019	236
Term loans originated in 2018	58
Term loans originated in 2017	47
Term loans originated in 2016	62
Term loans originated in 2015 and prior	203
Revolving loans	2
Total	$ 654