Employee Benefit Plans (Summary of the Fair Value Measurements by Type of Asset) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Total	$ 72,972	$ 70,627	$ 61,384
Cash [Member]
Total	268	245
U.S. Large Cap Growth [Member]
Total	7,165	6,650
U.S. Large Cap Value [Member]
Total	7,066	6,835
U.S. Small/Mid Cap Growth [Member]
Total	2,950	2,825
U.S. Small/Mid Cap Value [Member]
Total	2,721	2,784
Non-U.S. Core [Member]
Total	10,317	10,840
U.S. Large Cap Passive [Member]
Total	7,192	6,929
Emerging Markets [Member]
Total	703	711
U.S. Core Opportunistic [Member]
Total	24,019	22,720
U.S. Passive [Member]
Total	9,275	8,747
Opportunistic [Member]
Total	1,296	1,341
Fair Value, Inputs, Level 1 [Member]
Total	268	245
Fair Value, Inputs, Level 1 [Member] | Cash [Member]
Total	268	245
Fair Value, Inputs, Level 1 [Member] | U.S. Large Cap Growth [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Large Cap Value [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Small/Mid Cap Growth [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Small/Mid Cap Value [Member]
Total
Fair Value, Inputs, Level 1 [Member] | Non-U.S. Core [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Large Cap Passive [Member]
Total
Fair Value, Inputs, Level 1 [Member] | Emerging Markets [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Core Opportunistic [Member]
Total
Fair Value, Inputs, Level 1 [Member] | U.S. Passive [Member]
Total
Fair Value, Inputs, Level 1 [Member] | Opportunistic [Member]
Total
Fair Value, Inputs, Level 2 [Member]
Total	72,704	70,382
Fair Value, Inputs, Level 2 [Member] | Cash [Member]
Total
Fair Value, Inputs, Level 2 [Member] | U.S. Large Cap Growth [Member]
Total	7,165	6,650
Fair Value, Inputs, Level 2 [Member] | U.S. Large Cap Value [Member]
Total	7,066	6,835
Fair Value, Inputs, Level 2 [Member] | U.S. Small/Mid Cap Growth [Member]
Total	2,950	2,825
Fair Value, Inputs, Level 2 [Member] | U.S. Small/Mid Cap Value [Member]
Total	2,721	2,784
Fair Value, Inputs, Level 2 [Member] | Non-U.S. Core [Member]
Total	10,317	10,840
Fair Value, Inputs, Level 2 [Member] | U.S. Large Cap Passive [Member]
Total	7,192	6,929
Fair Value, Inputs, Level 2 [Member] | Emerging Markets [Member]
Total	703	711
Fair Value, Inputs, Level 2 [Member] | U.S. Core Opportunistic [Member]
Total	24,019	22,720
Fair Value, Inputs, Level 2 [Member] | U.S. Passive [Member]
Total	9,275	8,747
Fair Value, Inputs, Level 2 [Member] | Opportunistic [Member]
Total	$ 1,296	$ 1,341