Shareholders' Equity (Share Based Compensation) (Details) - USD ($)	3 Months Ended							9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2014	Sep. 30, 2017	Sep. 30, 2016	May 08, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding - January 1, Options (in shares)			902,775					902,775
Granted, Options (in shares)								185,500	18,500
Exercised, Options (in shares)								(74,699)
Forfeited or Expired, Options (in shares)								(3,381)
Outstanding - September 30, Options (in shares)	1,010,195							1,010,195
Exercisable -September 30, Options (in shares)	585,522							585,522
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding - January 1, Weighted Avg Exercise Price (in dollars per share)			$ 19.43					$ 19.43
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value								30.50
Exercised, Weighted Avg Exercise Price (in dollars per share)								19.04
Forfeited or Expired, Weighted Avg Exercise Price (in dollars per share)								24.67
Outstanding - September 30, Weighted Avg Exercise Price (in dollars per share)	$ 21.47							21.47
Exercisable - September 30, Weighted Avg Exercise Price (in dollars per share)	$ 18.58							$ 18.58
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized							500,000
Shares authorized										1,500,000
Remaining shares issuable under 2009 Plan	219,230							219,230
Allocated Share-based Compensation Expense								$ 1,300,000	$ 1,300,000
Income tax benefit								300,000	400,000
Unrecognized compensation cost related to unvested awards	$ 2,600,000							$ 2,600,000
Recognition weighted-average period								1 year 9 months 25 days
Exercised, Aggregate Intrinsic Value (In thousands)								$ 571,000
Outstanding - September 30, Weighted Avg Remaining Contractual Term								3 years 6 months 17 days
Outstanding - September 30, Aggregate Intrinsic Value (In thousands)	11,593,000							$ 11,593,000
Exercisable - September 30, Weighted Avg Remaining Contractual Term								2 years 5 months 11 days
Exercisable - September 30, Aggregate Intrinsic Value (In thousands)	$ 8,414,000							$ 8,414,000
Restricted Stock Awards Disclosure [Abstract]
Restricted Stock Awards, Value, Granted To Director								77,500	$ 77,500
Aggregate shares of restricted stock granted (in shares)	3,170	3,195	3,985	3,485	3,925	5,190
Issuance of restricted common stock for services	$ 97,000	$ 97,000	$ 97,000	$ 97,000	$ 97,000	$ 97,000		$ 290,000
Weighted average fair value per share (in dollars per share)	$ 30.55	$ 30.30	$ 24.30	$ 27.79	$ 24.68	$ 18.65
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Incentive Stock Option Plan, Term								10 years