INVESTMENT SECURITIES (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost and Fair Value of Available-for-Sale Investment Securities

The following table presents the amortized cost and fair value of the investment securities portfolio as of the dates indicated:



($ in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
September 30, 2018
Securities available-for-sale:
SBA loan pool securities	$	910	$	—	$	(22	)	$	888
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	472,581		—		(33,113		)	439,468
Non-agency residential mortgage-backed securities	439		12		—			451
Non-agency commercial mortgage-backed securities	135,558		—		(2,854		)	132,704
Collateralized loan obligations	1,481,415		6,835		(1,929		)	1,486,321
Total securities available-for-sale	$	2,090,903	$	6,847	$	(37,918	)	$	2,059,832
December 31, 2017
Securities available-for-sale:
SBA loan pool securities	$	1,056	$	2	$	—		$	1,058
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	492,255		10		(15,336		)	476,929
Non-agency residential mortgage-backed securities	741		16		(1		)	756
Non-agency commercial mortgage-backed securities	305,172		5,339		—			310,511
Collateralized loan obligations	1,691,455		11,129		(266		)	1,702,318
Corporate debt securities	76,714		7,183		—			83,897
Total securities available-for-sale	$	2,567,393	$	23,679	$	(15,603	)	$	2,575,469

Proceeds from Sales and Calls of Securities and Associated Gross Gains and Losses

The following table presents proceeds from sales and calls of securities available-for-sale and the associated gross gains and losses realized through earnings upon the sales and calls of securities available-for-sale for the periods indicated:



	Three Months Ended September 30,				Nine Months Ended September 30,
($ in thousands)	2018		2017		2018		2017
Gross realized gains on sales and calls of securities available-for-sale	$	13	$	7,625	$	5,532	$	12,080
Gross realized losses on sales and calls of securities available-for-sale	—		—		—		—
Net realized gains on sales and calls of securities available-for-sale	$	13	$	7,625	$	5,532	$	12,080
Proceeds from sales and calls of securities available-for-sale	$	283,114	$	312,961	$	896,070	$	1,199,551

Summary of Investment Securities with Unrealized Losses

The following table summarizes the investment securities with unrealized losses by security type and length of time in a continuous unrealized loss position as of the dates indicated:



	Less Than 12 Months					12 Months or Longer					Total
($ in thousands)	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
September 30, 2018
Securities available-for-sale:
SBA loan pool securities	$	888	$	(22	)	$	—	$	—		$	888	$	(22	)
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	$	14,964	$	(376	)	$	424,417	$	(32,737	)	$	439,381	$	(33,113	)
Non-agency residential mortgage-backed securities	78		—			44		—			122		—
Non-agency commercial mortgage-backed securities	132,703		(2,854		)	—		—			132,703		(2,854		)
Collateralized loan obligations	335,446		(1,929		)	—		—			335,446		(1,929		)
Total securities available-for-sale	$	484,079	$	(5,181	)	$	424,461	$	(32,737	)	$	908,540	$	(37,918	)
December 31, 2017
Securities available-for-sale:
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	$	4,880	$	(35	)	$	470,092	$	(15,301	)	$	474,972	$	(15,336	)
Non-agency residential mortgage-backed securities	—		—			148		(1		)	148		(1		)
Collateralized loan obligations	104,334		(266		)	—		—			104,334		(266		)
Total securities available-for-sale	$	109,214	$	(301	)	$	470,240	$	(15,302	)	$	579,454	$	(15,603	)