Incentive Plans (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Incentive Plans [Abstract]
Number of stock options outstanding (in shares)	0		0
Number of stock options granted (in shares)	0	0
Common stock reserved for issuance [Line Items]
Common shares reserved for issuance (in shares)	4,430
1993 Stock Incentive Plan [Member]
Common stock reserved for issuance [Line Items]
Common shares reserved for issuance (in shares)	4,320
Other employee benefit plan [Member]
Common stock reserved for issuance [Line Items]
Common shares reserved for issuance (in shares)	110