Other Liabilities (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Aug. 29, 2014
Other Liabilities [Line Items]
Accrued pension costs		$ 5,047,000		$ 5,228,000	$ 7,500,000
Service cost		0	$ 0
Interest cost		45,000	45,000
Actuarial loss (gain)		52,000	$ 52,000
Benefit obligation		$ 10,200,000
Discount rate		4.25%
Discount term		15 years
Monthly estate payment amount		$ 57,000
Discounted value		2,700,000
Accumulated prior service cost		$ 3,100,000
Accumulated prior service cost amortization period		15 years
Accrued pension costs included in other liabilities		$ 5,700,000
Payment related to annuity	$ 2,400,000
Payment period		42 months
Supplemental Executive Retirement Plans [Member]
Other Liabilities [Line Items]
Accrued pension costs					$ 7,600,000