Balance Sheet Offsetting (Tables)

3 Months Ended

Mar. 31, 2015

Offsetting [Abstract]

Balance Sheet Offsetting of Derivative Assets and Liabilities

	Gross amounts recognized		Gross amounts offset in the balance sheet		Net amounts presented in the balance sheet		Gross amounts not offset
							in the balance sheet
							Financial instruments			Collateral			Net amount
March 31, 2015	($ in Thousands)
Derivative assets:
Interest rate-related instruments	$	143	$	—	$	143	$	(143	)	$	—		$	—
Derivative liabilities:
Interest rate-related instruments	$	40,348	$	—	$	40,348	$	(143	)	$	(30,481	)	$	9,724
December 31, 2014
Derivative assets:
Interest rate-related instruments	$	558	$	—	$	558	$	(558	)	$	—		$	—
Derivative liabilities:
Interest rate-related instruments	$	34,087	$	—	$	34,087	$	(558	)	$	(26,105	)	$	7,424