Incentive Plans (Changes in Time-Lapse Restricted Stock and Restricted Stock Units Outstanding) (Details) - Restricted Stock and Restricted Stock Units [Member] - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Share based Compensation Arrangements by Share based Payment Award, Equity Instruments, Other Than Options, Restricted Stock Units [Line Items]
Balance at beginning of year	477,244	321,789	112,881
Granted	503,555	282,065	278,892
Vested and issued	(32,092)	(69,610)	(54,884)
Forfeited	(25,425)	(57,000)	(15,100)
Balance at end of year	923,282	477,244	321,789