Stock Compensation Plans and Other Employee Benefit Plans (Summary of Plans' Restricted Share Award Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock
Non-Option Equity Instruments Outstanding [Roll Forward]
Outstanding at the beginning of period (in shares)	137,593	146,112	181,522
Granted (in shares)	18,022	27,165	31,463
Vested and issued (in shares)	(20,007)	(29,018)	(60,121)
Forfeited (in shares)	(2,183)	(6,666)	(6,752)
Outstanding at the end of period (in shares)	133,425	137,593	146,112
Vested, but deferred at year end (in shares)	89,050	85,000	85,000
Non-Options Equity Instruments Outstanding, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding at beginning of the period (in dollars per share)	$ 49.63	$ 47.45	$ 43.39
Granted (in dollars per share)	46.01	48.17	45.00
Vested and issued (in dollars per share)	44.91	39.33	34.98
Forfeited (in dollars per share)	44.18	40.76	37.95
Outstanding at end of the period (in dollars per share)	49.94	49.63	47.45
Vested, but deferred at year end (in dollars per share)	$ 51.47	$ 51.88	$ 51.88
Performance Shares
Non-Option Equity Instruments Outstanding [Roll Forward]
Outstanding at the beginning of period (in shares)	276,533	295,679	307,512
Granted (in shares)	118,084	106,017	93,535
Vested and issued (in shares)	(78,410)	(78,590)	(15,944)
Forfeited (in shares)	(18,027)	(46,573)	(89,424)
Outstanding at the end of period (in shares)	298,180	276,533	295,679
Vested, but deferred at year end (in shares)	6,672	0	0
Non-Options Equity Instruments Outstanding, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding at beginning of the period (in dollars per share)	$ 43.01	$ 38.18	$ 34.01
Granted (in dollars per share)	41.02	44.35	46.86
Vested and issued (in dollars per share)	37.90	31.10	33.25
Forfeited (in dollars per share)	41.83	35.51	33.78
Outstanding at end of the period (in dollars per share)	43.64	43.01	38.18
Vested, but deferred at year end (in dollars per share)	$ 37.98	$ 0.00	$ 0.00