Earnings Per Share (Details) shares in Thousands		3 Months Ended
	Nov. 15, 2010 shares $ / shares	Mar. 31, 2016 shares	Mar. 31, 2015 shares
Reconciliation of Weighted-Average Diluted Shares Outstanding
Weighted average common shares outstanding - basic		41,608	36,349
Weighted Average Number of Shares Outstanding - Diluted		41,608	36,981
Anti-dilutive Effect
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1,331	62
Restricted stock
Reconciliation of Weighted-Average Diluted Shares Outstanding
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements		0	226
Anti-dilutive Effect
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		723	51
Convertible senior note
Reconciliation of Weighted-Average Diluted Shares Outstanding
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements		0	339
Anti-dilutive Effect
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		508	0
Other equity-based awards
Reconciliation of Weighted-Average Diluted Shares Outstanding
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements		0	67
Anti-dilutive Effect
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		100	11
3.25% Convertible Senior Notes due 2016
Convertible Senior Note Due 2016
3.25% Convertible Note, Shares To Be Received Upon Conversion (in thousands)	2,700
3.25% Convertible Note, Conversion Price | $ / shares	$ 42.40