Consumer Loans Receivable (Consumer Loan Receivables by Segment and Credit Quality Indicator) (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2018 USD ($) Credit_Quality_Indicator	Mar. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sensitivity Analysis, Change in Prepayment Rate	$ 1,200
Sensitivity Analysis, Change in Default Rate	3,300
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	100,493	$ 96,899
Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	57,185	56,086
Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 1,033	1,149
Chattel Loans Range One [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	0
Chattel Loans Range One [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	619
Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 26,908	26,041
Chattel Loans Range Two [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	620
Chattel Loans Range Two [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	719
Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 28,787	28,444
Chattel Loans Range Three [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	720
Chattel Loans Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 457	452
Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	29,091	26,126
Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 344	476
Conforming Mortgages Range One [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	0
Conforming Mortgages Range One [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	619
Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 18,532	15,044
Conforming Mortgages Range Two [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	620
Conforming Mortgages Range Two [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	719
Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 10,099	10,381
Conforming Mortgages Range Three [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	720
Conforming Mortgages Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 116
Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	14,207	14,676
Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 1,509	1,534
Non Conforming Mortgages Range One [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	0
Non Conforming Mortgages Range One [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	619
Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 8,273	8,591
Non Conforming Mortgages Range Two [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	620
Non Conforming Mortgages Range Two [Member] | Maximum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	719
Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 4,147	4,269
Non Conforming Mortgages Range Three [Member] | Minimum [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Asset class credit quality indicator | Credit_Quality_Indicator	720
Non Conforming Mortgages Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 278	282
Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	10	11
Loans Securitized 2005 [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	22,761	23,760
Loans Securitized 2005 [Member] | Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	20,342	21,210
Loans Securitized 2005 [Member] | Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	439	465
Loans Securitized 2005 [Member] | Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	9,668	10,102
Loans Securitized 2005 [Member] | Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	10,186	10,594
Loans Securitized 2005 [Member] | Chattel Loans Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	49	49
Loans Securitized 2005 [Member] | Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2005 [Member] | Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2005 [Member] | Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2005 [Member] | Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2005 [Member] | Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	2,419	2,550
Loans Securitized 2005 [Member] | Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	81	82
Loans Securitized 2005 [Member] | Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	1,061	1,120
Loans Securitized 2005 [Member] | Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	1,277	1,348
Loans Securitized 2005 [Member] | Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2007 [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	20,341	21,180
Loans Securitized 2007 [Member] | Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	13,299	13,871
Loans Securitized 2007 [Member] | Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	271	354
Loans Securitized 2007 [Member] | Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	6,889	7,107
Loans Securitized 2007 [Member] | Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	6,139	6,410
Loans Securitized 2007 [Member] | Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2007 [Member] | Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2007 [Member] | Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2007 [Member] | Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Securitized 2007 [Member] | Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	7,042	7,309
Loans Securitized 2007 [Member] | Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	398	405
Loans Securitized 2007 [Member] | Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	4,151	4,378
Loans Securitized 2007 [Member] | Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	2,493	2,526
Loans Securitized 2007 [Member] | Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Loans Unsecuritized [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	30,597	28,041
Loans Unsecuritized [Member] | Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	23,040	20,605
Loans Unsecuritized [Member] | Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	323	330
Loans Unsecuritized [Member] | Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	10,351	8,587
Loans Unsecuritized [Member] | Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	11,958	11,285
Loans Unsecuritized [Member] | Chattel Loans Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	408	403
Loans Unsecuritized [Member] | Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	2,801	2,608
Loans Unsecuritized [Member] | Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	155	156
Loans Unsecuritized [Member] | Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	2,232	2,137
Loans Unsecuritized [Member] | Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	298	199
Loans Unsecuritized [Member] | Conforming Mortgages Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	116
Loans Unsecuritized [Member] | Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	4,746	4,817
Loans Unsecuritized [Member] | Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	1,030	1,047
Loans Unsecuritized [Member] | Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	3,061	3,093
Loans Unsecuritized [Member] | Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	377	395
Loans Unsecuritized [Member] | Non Conforming Mortgages Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	278	282
Loans Unsecuritized [Member] | Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	10	11
Construction Advances [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	12,259	11,088
Construction Advances [Member] | Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	12,259	11,088
Construction Advances [Member] | Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	141
Construction Advances [Member] | Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	7,950	6,428
Construction Advances [Member] | Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	4,309	4,519
Construction Advances [Member] | Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Construction Advances [Member] | Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	14,535	12,830
Consumer Loans Held For Sale [Member] | Chattel Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	504	400
Consumer Loans Held For Sale [Member] | Chattel Loans Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member] | Chattel Loans Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	245
Consumer Loans Held For Sale [Member] | Chattel Loans Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	504	155
Consumer Loans Held For Sale [Member] | Conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	14,031	12,430
Consumer Loans Held For Sale [Member] | Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	189	179
Consumer Loans Held For Sale [Member] | Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	8,350	6,479
Consumer Loans Held For Sale [Member] | Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	5,492	5,663
Consumer Loans Held For Sale [Member] | Conforming Mortgages Range Four [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0
Consumer Loans Held For Sale [Member] | Non-conforming Mortgages [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member] | Non Conforming Mortgages Range One [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member] | Non Conforming Mortgages Range Two [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member] | Non Conforming Mortgages Range Three [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	0	0
Consumer Loans Held For Sale [Member] | Other Loans [Member]
Gross Consumer Loans Receivable by Portfolio Segment and Credit Risk Score
Consumer loans receivable	$ 0	$ 0