Employee Benefit and Deferred Compensation Plans (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	$ 26,532	$ 27,989
Cash and cash equivalents
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	1,882	10,971
U.S. large cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	9,144	3,622
U.S. mid cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	5,210	4,079
U.S. small cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	2,791	2,237
International companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	1,464	1,212
U.S. government bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	2,003	2,673
Other corporate bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	4,038	3,195
Quoted Prices In Active Markets for Identical Assets (Level 1)
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	20,491	22,121
Quoted Prices In Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	1,882	10,971
Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. large cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	9,144	3,622
Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. mid cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	5,210	4,079
Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. small cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	2,791	2,237
Quoted Prices In Active Markets for Identical Assets (Level 1) | International companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	1,464	1,212
Quoted Prices In Active Markets for Identical Assets (Level 1) | U.S. government bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Quoted Prices In Active Markets for Identical Assets (Level 1) | Other corporate bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2)
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	6,041	5,868
Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2) | U.S. large cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2) | U.S. mid cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2) | U.S. small cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2) | International companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Other Observable Inputs (Level 2) | U.S. government bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	2,003	2,673
Significant Other Observable Inputs (Level 2) | Other corporate bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	4,038	3,195
Significant Unobservable Inputs (Level 3)
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. large cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. mid cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. small cap companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | International companies
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. government bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	0	0
Significant Unobservable Inputs (Level 3) | Other corporate bonds
Fair values of defined benefit pension plan assets by category of the firm
Fixed income securities	$ 0	$ 0