Consolidated Balance Sheet - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Assets
Cash			$ 110,233
Investment securities			908,297
Loans			864,819
Loans, at fair value		$ 26,583	338,867
Allowance for losses		(21,425)
Net loans receivable		1,128,698
Other assets			58,827
Total assets		1,534,529	1,077,357
Liabilities
Other liabilities			3,836
Total liabilities			913,127
Stockholders' equity
Total stockholders' equity	[1]		164,230
Total equity		284,916	287,159
Total liabilities and equity			1,077,357
Medallion Bank and Other Controlled Subsidiaries [Member]
Assets
Investment in affiliates			302,147
Bank Holding Company Accounting [Member]
Assets
Cash		10,344
Federal funds sold		25,237
Equity investments		10,773
Investment securities		44,717
Loans		1,150,123
Allowance for losses		(21,425)
Net loans receivable		1,128,698
Accrued interest receivable		7,360
Property and equipment, net		1,128
Loan collateral in process of foreclosure		60,052
Goodwill and intangible assets		211,123
Deferred tax assets and other tax receivables, net		3,460
Other assets		31,637
Total assets		1,534,529
Liabilities
Accrued interest payable		4,246
Deposits		896,402
Short-term borrowings		179,692
Other liabilities		19,025
Long-term debt		150,248
Total liabilities		1,249,613
Commitments and contingencies
Stockholders' equity
Preferred stock (1,000,000 shares of $0.01 par value stock authorized-noneoutstanding)
Common stock (50,000,000 shares of $0.01 par value stock authorized- 27,390,066 shares at June 30, 2018 and 27,294,327 shares at December 31, 2017 issued)		274
Additional paid in capital		274,012
Treasury stock (2,951,243 shares at June 30, 2018 and December 31, 2017)		(24,919)
Accumulated other comprehensive loss		(255)
Retained earnings		8,568
Total stockholders' equity		257,680
Non-controlling interest in consolidated subsidiaries		27,236
Total equity		284,916
Total liabilities and equity		$ 1,534,529
Number of shares outstanding		24,438,823
Book value per share/net asset value per share		$ 10.54
Investment Company Accounting [Member]
Assets
Cash			12,690
Equity investments, at fair value			5,213
Net investments			610,135
Accrued interest receivable			547
Property and equipment, net			235
Investments other than securities			7,450
Other assets			4,465
Total assets			635,522
Liabilities
Accounts payable and accrued expenses			4,373
Accrued interest payable			3,831
Deferred tax liabilities and other tax payables			12,536
Funds borrowed			327,623
Total liabilities			348,363
Commitments and contingencies
Stockholders' equity
Preferred stock (1,000,000 shares of $0.01 par value stock authorized-noneoutstanding)
Common stock (50,000,000 shares of $0.01 par value stock authorized- 27,390,066 shares at June 30, 2018 and 27,294,327 shares at December 31, 2017 issued)			273
Additional paid in capital			273,716
Treasury stock (2,951,243 shares at June 30, 2018 and December 31, 2017)			(24,919)
Accumulated undistributed net investment loss			(65,592)
Net unrealized appreciation on investments, net of tax			103,681
Total stockholders' equity			287,159
Total equity			287,159
Total liabilities and equity			$ 635,522
Number of shares outstanding			24,438,084
Book value per share/net asset value per share			$ 11.80
Investment Company Accounting [Member] | Affiliated Entity [Member]
Assets
Investment in affiliates			$ 4,308
Investment Company Accounting [Member] | Medallion Bank and Other Controlled Subsidiaries [Member]
Assets
Investment in affiliates			302,147
Investment Company Accounting [Member] | Parent Loan [Member]
Assets
Loans, at fair value			208,279
Investment Company Accounting [Member] | Commercial Loans [Member]
Assets
Loans, at fair value			53,737
Investment Company Accounting [Member] | Commercial Loans to Affiliated Entities [Member]
Assets
Loans, at fair value			999
Investment Company Accounting [Member] | Commercial Loans To Controlled Subsidiaries [Member]
Assets
Loans, at fair value			$ 35,452

[1] Includes $152,267 of unrealized appreciation on Medallion Bank, in excess of Medallion Bank's book value as of December 31, 2017.