Parent Company Stock Based Compensation - RSUs Granted Employees and Key Executive Officers Under Parent Company Stock Based Compensation Programs (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Shares outstanding
Outstanding at beginning of period (in shares)	1,582
Granted (in shares)	757
Settled (in shares)	(834)
Forfeited or expired (in shares)	(96)
Outstanding at end of period (in shares)	1,409
RSUs unvested and expected to vest at end of period (in shares)	1
RSUs vested and payable at end of period (in shares)	0
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 27.34
Granted (in dollars per share)	$ 35.97
Settled (in dollars per share)	$ 25.64
Forfeited or expired (in dollars per share)	$ 30.70
Outstanding at end of period (in dollars per share)	$ 32.75
RSUs unvested and expected to vest at end of period (in dollars per share)	$ 33.87
RSUs vested and payable at end of period	$ 27.51
Weighted-Average Remaining Contractual Term
RSUs at beginning of period (in years)	1 year 1 month 6 days
RSUs unvested and expected to vest at end of period (in years)	1 year 6 months
RSU's vested and payable at end of period (in years)	1 year 9 months 18 days