Share-Based Compensation (Summary Nonvested Share Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Weighted Average Grant Date Fair Value
Beginning of period (in dollars per share)	$ 4.72	$ 3.45	$ 2.69
Granted (in dollars per share)	$ 8.24	$ 6.81	$ 4.74
Vested (in dollars per share)	$ 3.90	$ 3.09	$ 2.61
Forfeited (in dollars per share)	$ 6.05	$ 4.77	$ 2.92
End of period (in dollars per share)	$ 6.17	$ 4.72	$ 3.45
Number of Non-vested Shares
Beginning of period (in shares)	1,559	1,592	1,489
Granted (in shares)	535	564	601
Vested (in shares)	(517)	(518)	(423)
Forfeited (in shares)	(112)	(79)	(75)
End of period (in shares)	1,465	1,559	1,592