Segment Reporting (Certain Information by Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended											12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014		Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 33,929	[1]	$ 144,598	[2],[3]	$ 113,645	$ 46,977	$ 56,886	[2]	$ 186,707	$ 200,985	$ 82,986	$ 339,149	$ 527,564	$ 553,615	$ 581,288
Income (loss) from operations	(75,292)	[1]	(36,490)	[2],[3]	(3,149)	(25,705)	(18,642)	[2]	698	42,900	(4,125)	(140,636)	20,831	34,922	64,066
Total assets	260,192						475,818		511,072			260,192	475,818	511,072	428,905
United Kingdom [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales							5,743					39,806		62,250
United States [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales							39,145					232,736	368,031	386,983	424,816
Income (loss) from operations							(19,782)					(147,457)	(11,788)	(1,257)	28,076
Total assets	217,924						423,874		420,329			217,924	423,874	420,329	328,975
International [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales							17,741					106,413	159,533	166,632	156,472
Income (loss) from operations							1,140					6,821	32,619	36,179	35,990
Total assets	$ 42,268						$ 51,944		$ 90,743			$ 42,268	$ 51,944	$ 90,743	$ 99,930

[1] Includes a tax benefit due to the release of valuation allowances. Refer to Note 11 - "Income Taxes" for additional information.

[2] Includes a tax provision due to the increase of valuation allowance. Refer to Note 11 - "Income Taxes" for additional information.

[3] Includes a goodwill impairment charge. Refer to Note 7 - "Goodwill" for additional information.