Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2012

Retirement Plans [Abstract]

Net period benefit cost for the pension and postretirement plans

		Three Months Ended				Six Months Ended			Year Ended
		June 30,				June 30,			December 31,
		2012		2011		2012		2011	2011
Components of Net Periodic Benefit Cost		($ in Thousands)
Pension Plan:
Service cost	$	2,612	$	2,613	$	5,225	$	5,225	$	9,898
Interest cost		1,612		1,589		3,225		3,180		6,414
Expected return on plan assets		(3,557)		(3,220)		(7,115)		(6,440)		(12,896)
Amortization of prior service cost		18		17		35		35		72
Amortization of actuarial loss		640		452		1,280		903		2,024
Total net periodic benefit cost	$	1,325	$	1,451	$	2,650	$	2,903	$	5,512
Postretirement Plan:
Interest cost	$	48	$	50	$	95	$	100	$	198
Amortization of prior service cost		42		99		85		198		395
Total net periodic benefit cost	$	90	$	149	$	180	$	298	$	593