INVESTMENT SECURITIES (Tables)

6 Months Ended

Jun. 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
June 30, 2018
Securities available-for-sale:
SBA loan pool securities	$	982	$	—	$	(15	)	$	967
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	485,503		—		(28,713		)	456,790
Non-agency residential mortgage-backed securities	483		15		(2		)	496
Non-agency commercial mortgage-backed securities	160,970		7		(2,619		)	158,358
Collateralized loan obligations	1,676,611		6,996		(3,094		)	1,680,513
Total securities available-for-sale	$	2,324,549	$	7,018	$	(34,443	)	$	2,297,124
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 June 30,				Six Months Ended June 30,
($ in thousands)	2018		2017		2018		2017
Gross realized gains on sales and calls of securities available-for-sale	$	278	$	1,099	$	5,519	$	4,455
Gross realized losses on sales and calls of securities available-for-sale	—		—		—		—
Net realized gains on sales and calls of securities available-for-sale	$	278	$	1,099	$	5,519	$	4,455
Proceeds from sales and calls of securities available-for-sale	$	325,439	$	475,586	$	612,956	$	886,590
Tax expense on sales and calls of securities available-for-sale	$	81	$	457	$	1,618	$	1,853

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
June 30, 2018
Securities available-for-sale:
SBA loan pool securities	$	966	$	(15	)	$	—	$	—		$	966	$	(15	)
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities	$	16,907	$	(374	)	$	436,740	$	(28,339	)	$	453,647	$	(28,713	)
Non-agency residential mortgage-backed securities	95		(1		)	61		(1		)	156		(2		)
Non-agency commercial mortgage-backed securities	152,392		(2,619		)	—		—			152,392		(2,619		)
Collateralized loan obligations	295,281		(3,094		)	—		—			295,281		(3,094		)
Total securities available-for-sale	$	465,641	$	(6,103	)	$	436,801	$	(28,340	)	$	902,442	$	(34,443	)
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	)