Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2022		Dec. 31, 2021
Investments at amortized cost	$ 2,792,773	[1],[2]	$ 2,432,012	[3],[4],[5]
Restricted cash	15,627		14,399
Deferred financing costs	$ 19,136		$ 19,147
Preferred stock, par value	$ 0.01		$ 0.01
Preferred stock, shares authorized	100,000,000		100,000,000
Preferred stock, shares issued	0		0
Preferred stock, shares outstanding	0		0
Common shares, par value	$ 0.01		$ 0.01
Common shares, authorized	400,000,000		400,000,000
Common shares, issued	81,647,551		76,067,586
Common shares, outstanding	81,170,965		75,771,542
Treasury stock, shares	476,586		296,044
Non-controlled, Non-affiliated Investments
Investments at amortized cost	$ 2,727,409		$ 2,354,984
Non-controlled, Affiliated Investments
Investments at amortized cost	0		12,666
Controlled, Affiliated Investments
Investments at amortized cost	$ 65,364		$ 64,362

[1] As of September 30, 2022, the estimated cost basis of investments for U.S. federal tax purposes was $2,807,880, resulting in estimated gross unrealized gains and losses of $117,489 and $109,905, respectively.

[2] The amortized cost represents the original cost adjusted for the amortization of discounts and premiums, as applicable, on debt investments using the effective interest method.

[3] As of December 31, 2021, the estimated cost basis of investments for U.S. federal tax purposes was $2,445,863, resulting in estimated gross unrealized gains and losses of $156,819 and $79,599, respectively.

[4] Certain portfolio company investments are subject to contractual restrictions on sales.

[5] The amortized cost represents the original cost adjusted for the amortization of discounts and premiums, as applicable, on debt investments using the effective interest method.