Segment Reporting and Significant Customer Information - Operating Results from Continuing Operations and Assets by Business Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Summary of operating results from continuing operations and assets by business segment
Revenues	$ 37,028	$ 35,447	$ 39,360	$ 39,333	$ 35,156	$ 38,661	$ 37,565	$ 36,960	$ 151,168		$ 148,342		$ 112,784
Intersegment revenues									0		0		0
Total net revenues									151,168		148,342		112,784
Operating income	4,358	4,195	10,366	6,570	8,175	9,225	7,629	(10,007)	25,489		15,022		23,512
North America
Summary of operating results from continuing operations and assets by business segment
Revenues									108,787		108,549		87,661
Intersegment revenues									728		466		197
Total net revenues									109,515		109,015		87,858
Operating income									21,481		30,110		24,998
Europe
Summary of operating results from continuing operations and assets by business segment
Revenues									42,381		39,793		25,123
Intersegment revenues									143		134		107
Total net revenues									42,524		39,927		25,230
Operating income									7,008		4,912		(1,489)
Elimination
Summary of operating results from continuing operations and assets by business segment
Revenues													0
Intersegment revenues													(304)
Total net revenues													(304)
Operating income													3
Elimination and Other (a)
Summary of operating results from continuing operations and assets by business segment
Revenues									0	[1]	0	[1]
Intersegment revenues									(871)	[1]	(600)	[1]
Total net revenues									(871)	[1]	(600)	[1]
Operating income									$ (3,000)	[1]	$ (20,000)	[1]

[1] Amount represents a charge related to unexchanged promotional merger shares of $3.0 million and $20.0 million for the years ended December 31, 2012 and 2011, respectively.