Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Summary of lending-related and other commitments

The following is a summary of lending-related commitments.

	2017		2016
	($ in Thousands)
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale (a) (b)	$	8,027,187	$	8,131,131
Commercial letters of credit (a)	11,886		7,923
Standby letters of credit (c)	235,361		259,632

(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 December 31, 2017 and 2016.

(b) Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 14.

(c)

The Corporation has established a liability of $2 million at December 31, 2017 and $3 million at December 31, 2016, 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 for the years ended as follows.

	2017			2016
	($ in Thousands)
Balance at beginning of year	$	900		$	1,197
Repurchase provision expense	246			456
Adjustments to provision expense	—			(750		)
Charge offs, net	(159		)	(3		)
Balance at end of year	$	987		$	900