Common Stock (Share-Based Compensation, Treasury Stock, and Stock Repurchase Plan) (Details) - USD ($)		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015	Nov. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash share-based compensation expense		$ 12,100,000	$ 13,100,000	$ 9,100,000
Common stock shares purchased as payment of income tax withholding (in shares)		238,216	473,304	243,005
Stock surrendered for exercise of stock options (in shares)		3,225	106,810	46,208
Treasury stock shares retired (in shares)	5,873,291
Treasury stock shares retired, cost	$ 32,600,000			$ 0
Common stock shares purchased, cost			$ 9,697,000	$ 10,395,000
Remaining authorized repurchase amount		$ 54,900,000
Restated Revolving Credit, Term Loan and Security Agreement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share repurchase covenant		$ 4,900,000
Share Repurchase Program, November 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase shares authorized						$ 25,000,000
Common stock shares purchased by the company (in shares)		0	799,723	621,176
Common stock shares purchased, cost			$ 9,700,000	$ 10,400,000
Common stock shares purchased, average cost per share (in dollars per share)			$ 12.13	$ 16.74
Share Repurchase Program, June 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase shares authorized					$ 50,000,000
Common stock shares purchased by the company (in shares)		0
Treasury Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares purchased as payment of income tax withholding (in shares)		238,000	473,000	243,000
Stock surrendered for exercise of stock options (in shares)		3,000	107,000	46,000
Treasury stock shares retired (in shares)				5,873,000
Treasury stock shares retired, cost	(32,600,000)			$ (32,568,000)
Common stock shares purchased by the company (in shares)			800,000	621,000
Common stock shares purchased, cost			$ 9,697,000	$ 10,395,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock shares retired (in shares)				5,873,000
Treasury stock shares retired, cost	(1,000)			$ 1,000
Additional Paid-in Capital
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock shares retired, cost	$ (32,600,000)			$ 32,567,000