Equity - Schedule of Stock Options, SARs, and Non-vested Restricted Stock Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Number of Outstanding of Stock Options and SARs	747,573	718,143	664,245	788,748
Stock Options and SARs Outstanding, Weighted Average Exercise Price	$ 26.68	$ 25.12	$ 23.78	$ 20.89
Stock Options and SARs Grants in Period, Net of Forfeitures	119,110	87,600	94,017
Stock Options and SARs Grants in Period, Weighted Average Exercise Price	$ 32.25	$ 34.92	$ 31.24
Stock Options and SARs Exercises in Period	86,680	23,035	208,877
Stock Options and SARs Exercises in Period, Weighted Average Exercise Price	$ 21.32	$ 20.83	$ 16.24
Stock Options and SARs Forfeitures and Expirations in Period	3,000	10,667	9,643
Stock Options and SARs Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 30.05	$ 31.16	$ 23.02
Exercisable Number of Stock Options and SARs	543,698	548,180	483,216
Stock Options and SARs Exercisable, Weighted Average Exercise Price	$ 24.34	$ 23.12	$ 22.83
Outstanding Non-Vested Restricted Stock	132,651	103,772	98,285	91,311
Restricted Stock, Nonvested, Weighted Average Grant Date Fair Value	$ 32.12	$ 31.24	$ 27.66	$ 18.75
Restricted Stock, Grants in Period	76,616	57,590	73,985
Restricted Stock Awarded, Weighted Average Grant Date Fair Value	$ 32.14	$ 33.88	$ 30.27
Restricted Stock, Forfeited in Period	0	8,360	1,000
Restricted Stock, Forfeitures, Weighted Average Grant Date Fair Value	$ 0.00	$ 21.72	$ 31.42
Restricted Stock, Net of Forfeitures Stock Issued During Period, Shares,	47,737	43,743	66,011
Restricted Stock, Vested in Period, Weighted Average Grant Date Fair Value	$ 30.25	$ 28.48	$ 18.21