Incentive Plan - Stock Options Outstanding (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Number of Options Granted
Outstanding, beginning of period | shares	175
Options expired | shares	(152)
Outstanding, end of period | shares	23
Exercisable, end of period, number of options granted | shares	23
Vested or expected to vest, end of period, number of options granted | shares	23
Outstanding, beginning of period, weighted average exercise price (dollars per share) | $ / shares	$ 26.29
Options expired, weighted average exercise price (dollars per share) | $ / shares	26.84
Outstanding, end of period, weighted average exercise price (dollars per share) | $ / shares	22.66
Exercisable, end of period, weighted average exercise price (dollars per share) | $ / shares	22.66
Vested or expected to vest, end of period, weighted average exercise price (dollars per share) | $ / shares	$ 22.66
Outstanding, end of period, weighted average remaining contractual term (years)	8 months 12 days
Exercisable, end of period, weighted average remaining contractual term (years)	8 months 12 days
Vested or expected to vest, end of period, weighted average remaining contractual term (years)	8 months 12 days
Outstanding, end of period, aggregate intrinsic value | $	$ 0
Exercisable, end of period, aggregate intrinsic value | $	0
Vested or expected to vest, end of period, aggregate intrinsic value | $	$ 0