Benefit Plans Benefit Plans (Detail 11) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 753,030	$ 764,164
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	96,071	106,166
Company Stock
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,725	3,827
U.S. Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	51,072	50,606
International Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	78,258	89,527
Emerging Markets Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	36,045	37,248
Fixed Income Securities, Corporate and Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	62,041	59,318
Fixed Income Mutual Funds, Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	16,869	15,968
Fixed Income Mutual Funds, Core Bond
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	164,661	206,823
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,021	57,191
Real Asset Mutual Funds, Commodities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	50,656	33,718
Other Types of Investments, Global Allocation Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	35,595	33,129
Other Types of Investments, Multi-Strategy Fund of Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	78,650	56,398
Other Types of Investments, Convertible Preferred Equity Certificates
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	14,366	14,245
Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	512,625	506,396
Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	96,071	106,166
Level 1 | Company Stock
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,725	3,827
Level 1 | U.S. Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	30,923	30,820
Level 1 | International Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	37,565	44,648
Level 1 | Emerging Markets Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	31,712	31,253
Level 1 | Fixed Income Securities, Corporate and Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	62,041	59,318
Level 1 | Fixed Income Mutual Funds, Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 1 | Fixed Income Mutual Funds, Core Bond
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	132,430	175,754
Level 1 | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	65,021	30,190
Level 1 | Real Asset Mutual Funds, Commodities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	24,582	0
Level 1 | Other Types of Investments, Global Allocation Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	28,555	24,420
Level 1 | Other Types of Investments, Multi-Strategy Fund of Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 1 | Other Types of Investments, Convertible Preferred Equity Certificates
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	123,912	164,733
Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 | Company Stock
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 | U.S. Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	20,149	19,786
Level 2 | International Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	40,693	44,879
Level 2 | Emerging Markets Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,333	5,995
Level 2 | Fixed Income Securities, Corporate and Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 | Fixed Income Mutual Funds, Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	15,208	14,412
Level 2 | Fixed Income Mutual Funds, Core Bond
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	32,231	31,069
Level 2 | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	27,001
Level 2 | Real Asset Mutual Funds, Commodities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	4,258	12,882
Level 2 | Other Types of Investments, Global Allocation Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	7,040	8,709
Level 2 | Other Types of Investments, Multi-Strategy Fund of Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 2 | Other Types of Investments, Convertible Preferred Equity Certificates
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	116,493	93,035	43,386
Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Company Stock
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | U.S. Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | International Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Emerging Markets Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Fixed Income Securities, Corporate and Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Fixed Income Mutual Funds, Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	1,661	1,556	2,114
Level 3 | Fixed Income Mutual Funds, Core Bond
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Real Estate
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Real Asset Mutual Funds, Commodities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	21,816	20,836	0
Level 3 | Other Types of Investments, Global Allocation Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Level 3 | Other Types of Investments, Multi-Strategy Fund of Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	78,650	56,398	23,064
Level 3 | Other Types of Investments, Convertible Preferred Equity Certificates
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 14,366	$ 14,245	$ 12,909