Stock Based Compensation (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense related to stock awards	$ 2.5	$ 1.7	$ 3.1	$ 2.3
Amortization of unvested shares	1.1	0.5	1.7	1.1
Total shares issued to employees, directors, and officers			130,828
Unrecognized compensation cost related to nonvested	$ 4.7		$ 4.7
Unrecognized compensation cost related to nonvested, weighted-average vesting period (in years)			2 years
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of predetermined peer group's total stockholder return			3 years