Commitments, Off-Balance Sheet Arrangements, Legal Proceedings and Regulatory Matters (Tables)

3 Months Ended

Mar. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Summary of lending-related and other commitments

The following is a summary of lending-related commitments.

	March 31, 2018		December 31, 2017
	($ in Thousands)
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a) (b)	$	8,481,563	$	8,027,187
Commercial letters of credit (a)	12,456		11,886
Standby letters of credit (c)	253,857		235,361

(a) These off-balance sheet financial instruments are exercisable at the market rate prevailing at the date the underlying transaction will be completed and, thus, are deemed to have no current fair value, or the fair value is based on fees currently charged to enter into similar agreements and is not material at March 31, 2018 or December 31, 2017.

(b) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 10.

(c) The Corporation has established a liability of $2 million at March 31, 2018 and December 31, 2017, as an estimate of the fair value of these financial instruments.

Summary of changes in the residential mortgage repurchase reserve

The following summarizes the changes in the mortgage repurchase reserve.

	Three Months Ended March 31, 2018			Year Ended December 31, 2017
	($ in Thousands)
Balance at beginning of period	$	987		$	900
Repurchase provision expense	56			246
Charge offs, net	(48		)	(159		)
Amount recorded at acquisition	88			—
Balance at end of period	$	1,083		$	987