Defined Benefit Pension and Other Post Retirement Plans (Details Textual) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2007	Mar. 31, 2011	Dec. 31, 2012 Employee	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Pension and Other Post Retirement Plans (Textual) [Abstract]
Number of consecutive years of annual compensation earned			5 years
Numbers of years of employment			10 years
Additional service period granted under pension plan			5 years
Period for defined contribution plan	5 years		5 years
Number of Employees transferred			5,100
Pension plan assets				$ 238,833	$ 238,833
Pension plan liabilities				339,799	339,799
Reduction in the net unfunded liability non-cash settlement gain				100,966
Actuarial loss				129,665
Pension settlement charge				28,699
Reimbursed the contributions by the company related to the 2010 plan year				8,233
Net charge before taxes		20,466		20,466	(8,572)
Deferred tax adjustments				7,143
Discount rate used to determine benefit obligations for Pension Plan			4.10%	4.69%
Estimated net actuarial loss that will be amortized into periodic benefit cost in 2013			4,500
Contribution by the Company for the pension plan			19,226	27,157	14,287
Expected contribution by the company for pension plan			20,000
Plan assets expected to be returned			0
Expenses for post-retirement benefit plan recognized			$ 94	$ 121	$ 76