Employee Benefit Plans (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) officers	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
401(k) Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Minimum age requirement	21 years
Minimum service period required	3 months
Employer matching contribution, percent of match	75.00%
Maximum annual contribution per employee, percent	8.00%
Total cost recognized for the period	$ 4,200,000	$ 5,200,000	$ 4,400,000
Postretirement Life Insurance
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Death benefit received by the Company	$ 1,800,000	0	382,000
Base amount of death proceeds, annual percentage increase until retirement age is reached	3.00%
Period death benefit required to be paid within following participant's death	90 days
Total cost recognized for the period	$ 7,900,000	6,900,000	7,800,000
Deferred compensation plan | Directors and officers
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation liability	765,000	1,000,000.0
Deferred compensation plan, period expense	34,000	22,000	21,000
Long term incentive plan | Named executive officers ('NEO')
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation plan, period expense	$ 513,000	$ 510,000	$ 455,000
Number of officers currently participating in the LTIP | officers	2
Long term incentive plan | Named executive officers ('NEO') | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation plan, requisite service period	5 years
Long term incentive plan | Named executive officers ('NEO') | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation plan, requisite service period	10 years
Vested after 2 Years of Service | 401(k) Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution, vesting percentage	25.00%
Vested after 3 Years of Service | 401(k) Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution, vesting percentage	50.00%
Vested after 4 Years of Service | 401(k) Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution, vesting percentage	75.00%
Vested after 5 or More Years of Service | 401(k) Savings Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution, vesting percentage	100.00%