Employee Benefit Plans (Fair Value Measurement Levels For Qualified Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Cash	$ 437,474	$ 611,382
Short-term investments, which approximates fair value	14,328	10,590
Multi-strategy equity fund, fair value	10,629	10,765
Private equity limited partnerships	11,423	9,156
Total	157,090	152,446
Percent of fixed income funds in US securities	50.00%	50.00%
Percent of fixed income funds in international securities	50.00%	50.00%
Percent of equities mutual funds in US equities	90.00%	90.00%
Percent of equities mutual funds in international equities	10.00%	10.00%
Cash Managed By Employee Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	23,948	24,630
Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	96,762	97,305
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value	14,328	10,590
Total	135,037	132,525
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Cash Managed By Employee Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	23,948	24,630
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value	96,762	97,305
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Short-term investments, which approximates fair value
Multi-strategy equity fund, fair value
Private equity limited partnerships
Total
Significant Other Observable Inputs (Level 2) [Member] | Cash Managed By Employee Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value
Significant Other Observable Inputs (Level 2) [Member] | Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Mutual funds, fair value
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Multi-strategy equity fund, fair value	10,629	10,765
Private equity limited partnerships	11,423	9,156
Total	22,053	19,921
Significant Unobservable Inputs (Level 3) [Member] | Cash Managed By Employee Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash
Parent Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash	$ 1,398	$ 3,643