Loan status forbearance recorded investment.

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- Definition

Loan status in school grace and deferment recorded investment.

+ References

No definition available.

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- Definition

Total loans in repayment.

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No definition available.

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- Definition

Loans in repayment and percentage of each status.

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No definition available.

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- Definition

Loans in repayment current in percentage.

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No definition available.

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- Definition

Total loans in repayment, in percentage.

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No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Percentage of financing receivable balance that is past due.

+ References

No definition available.

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- Definition

Financing receivables that are current.

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- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Allowance for Loan Losses - Loan Status and Aging of Past Due TDR Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
TDR loans in repayment and percentage of each status:
Allowance for loan losses	$ (295,277)	$ (272,123)	$ (251,475)	$ (207,448)	$ (187,086)	$ (184,701)
Loans held for investment, net	20,308,581		18,567,641
Student Loan \| Consumer Portfolio Segment \| Troubled Debt Restructured Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR loans in in-school/grace/deferment	57,595		51,745
TDR loans in forbearance	59,682		69,652
TDR loans in repayment and percentage of each status:
Loans current	917,138		774,222
Total TDR loans in repayment	$ 1,004,539		$ 868,954
Loans current (as a percentage)	91.30%		89.10%
Total TDR loans in repayment	100.00%		100.00%
Total Private Education Loans, gross	$ 1,121,816		$ 990,351
Student Loan \| Consumer Portfolio Segment \| Loans delinquent 31-60 days \| Troubled Debt Restructured Loans
TDR loans in repayment and percentage of each status:
Loans delinquent	$ 45,080		$ 48,377
Loans delinquent (as a percentage)	4.50%		5.60%
Student Loan \| Consumer Portfolio Segment \| Loans delinquent 61-90 days \| Troubled Debt Restructured Loans
TDR loans in repayment and percentage of each status:
Loans delinquent	$ 25,580		$ 28,778
Loans delinquent (as a percentage)	2.50%		3.30%
Student Loan \| Consumer Portfolio Segment \| Loans delinquent, greater than 90 days \| Troubled Debt Restructured Loans
TDR loans in repayment and percentage of each status:
Loans delinquent	$ 16,741		$ 17,577
Loans delinquent (as a percentage)	1.70%		2.00%