|
Employee Benefit Plans (Details) (USD $)
|
12 Months Ended |
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
| Employees' Stock Ownership Plan |
|
|
|
| Number of allocated shares acquired prior to December 31, 1992 |
479,755 |
543,471 |
|
| Associated fair values of allocated shares acquired prior to December 31, 1992 |
$ 3,100,000 |
$ 3,200,000 |
|
| Shares |
|
|
|
| Allocated shares |
171,988 |
192,171 |
|
| Fair Value |
|
|
|
| Allocated shares, Fair Value |
1,100,000 |
1,100,000 |
|
| Profit Sharing Plan |
|
|
|
| Vesting period |
5 years |
|
|
| Expenses related to employee benefit plans |
|
|
|
| Employee benefits |
2,636,000 |
2,975,000 |
3,024,000 |
| Interest on employee stock ownership plan debt |
|
|
5,000 |
| Total employer contributions |
2,636,000 |
2,975,000 |
3,029,000 |
| Deferred compensation plans for deferral of performance bonuses |
|
|
|
| Deferred compensation expense |
300,000 |
200,000 |
200,000 |
| Deferred compensation liability |
$ 5,100,000 |
$ 4,800,000 |
$ 4,500,000 |