Employee Benefit Plans (Pension Plan Assets Fair Value Measurements) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,990	$ 3,414	$ 6,824
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	103,781	106,620	$ 134,017
Pension Benefits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,600	33,863
Pension Benefits | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	89,191	69,343
Pension Benefits | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,990	3,414
Pension Benefits | Insurance contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,765	1,760
Pension Benefits | Insurance contracts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Insurance contracts [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,765	1,760
Pension Benefits | Insurance contracts [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,302
Pension Benefits | Cash [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,302
Pension Benefits | Cash [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Pension Benefits | Cash [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Pension Benefits | Cash, mutual funds, and common stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5,429
Pension Benefits | Cash, mutual funds, and common stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5,429
Pension Benefits | Cash, mutual funds, and common stock [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Pension Benefits | Cash, mutual funds, and common stock [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Pension Benefits | Marketable equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,298	28,434
Pension Benefits | Marketable equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,298	28,434
Pension Benefits | Marketable equity securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Marketable equity securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Common collective trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	76,969	56,327
Pension Benefits | Common collective trusts [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Common collective trusts [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	76,969	56,327
Pension Benefits | Common collective trusts [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Investment partnership [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,447	14,670
Pension Benefits | Investment partnership [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Pension Benefits | Investment partnership [Member] | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10,457	11,256
Pension Benefits | Investment partnership [Member] | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,990	$ 3,414