Retirement Plans

The Corporation has a noncontributory defined benefit retirement plan (the Retirement Account Plan (“RAP”)) covering substantially all full-time employees. The benefits are based primarily on years of service and the employee’s compensation paid. Employees of acquired entities generally participate in the RAP after consummation of the business combinations. Any retirement plans of acquired entities are typically merged into the RAP after completion of the mergers, and credit is usually given to employees for years of service at the acquired institution for vesting and eligibility purposes.

The Corporation also provides legacy healthcare access to a limited group of retired employees from a previous acquisition in the Postretirement Plan. There are no other active retiree healthcare plans.

The components of net periodic benefit cost for the RAP and Postretirement Plans for three and six months ended June 30, 2017 and 2016 were as follows.



	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
	($ in Thousands)
Components of Net Periodic Benefit Cost
Pension Plan:
Service cost	$	1,782		$	1,725		$	3,563		$	3,450
Interest cost	1,756			1,780			3,512			3,560
Expected return on plan assets	(4,882		)	(5,065		)	(9,763		)	(10,130		)
Amortization of prior service cost	(18		)	12			(37		)	25
Amortization of actuarial loss	487			483			975			965
Total net pension cost	$	(875	)	$	(1,065	)	$	(1,750	)	$	(2,130	)
Postretirement Plan:
Interest cost	$	24		$	36		$	48		$	72
Amortization of prior service cost	(19		)	—			(38		)	—
Total net periodic benefit cost	$	5		$	36		$	10		$	72