Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 18, 2015	Mar. 09, 2015
Debt Instrument [Line Items]
Gross long-term debt	$ 310,578
Less unamortized debt issuance costs	(5,065)	$ (5,527)
Total long-term debt	305,513	436,280
Subordinated Notes [Member] | Subordinated Notes Payable, Maturing June 2045 [Member]
Debt Instrument [Line Items]
Gross long-term debt	150,000	150,000		$ 150,000
Less unamortized debt issuance costs	$ (4,780)
Notes payable maturity date	Jun. 15, 2045
Subordinated Notes [Member] | Subordinated Notes Payable Maturing On April 2017 [Member]
Debt Instrument [Line Items]
Gross long-term debt		95,511
Term Note [Member] | Term Note Payable, Maturing December 2018 [Member]
Debt Instrument [Line Items]
Gross long-term debt	$ 89,200	107,100	$ 125,000
Less unamortized debt issuance costs	$ (285)
Notes payable maturity date	Dec. 18, 2018
Other Long-Term Debt [Member]
Debt Instrument [Line Items]
Gross long-term debt	$ 71,378	$ 89,196