Employee Benefit Plans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Contribution	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Tax-exempt interest earned on the life insurance policies	$ 1,864	$ 1,908	$ 1,881
Executive Officers [Member] | Executive Retirement Plan and Life Insurance Arrangements [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Employer contribution	3,800	3,500	2,700
Total accrued liability	37,400	31,300
Tax-exempt interest earned on the life insurance policies	1,864	1,908	1,881
Cash surrender value of life insurance policies	57,800	55,900
Senior Level Employees [Member] | Senior Management Retention Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Employer contribution	627	530	475
Total accrued liability	$ 3,400	2,300
Pension Plan [Member] | Profit Sharing Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Minimum requisite service period	1 year
Number of annual employer contribution | Contribution	2
Employer discretionary contribution amount	$ 975	925	875
Employer mandatory contributions amount	$ 1,200	$ 1,100	$ 1,000
Annual vesting percentage, first year	0.00%
Annual vesting percentage, full year thereafter	25.00%
Benefit vesting period	5 years