Business Information - Information by Geographic Region, After Elimination of All Significant Inter-company Accounts and Transactions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Disclosure [Line Items]
Total revenues	$ 76,300	$ 44,600	$ 86,700	$ 79,600	$ 92,300	$ 62,700	$ 47,300	$ 82,700	$ 287,152	$ 285,079	$ 293,993
Income (loss) before taxes	21,100	3,000	25,400	21,700	28,100	13,900	3,500	24,800	71,206	70,475	68,670
Total assets	353,446				386,970				353,446	386,970	460,740
Americas
Segment Reporting Disclosure [Line Items]
Total revenues									160,082	179,204	153,812
Income (loss) before taxes									30,264	56,837	22,812
Total assets	144,462				166,128				144,462	166,128	192,111
Europe
Segment Reporting Disclosure [Line Items]
Total revenues									84,360	57,606	60,068
Income (loss) before taxes									34,349	8,447	12,578
Total assets	54,772				40,758				54,772	40,758	74,689
Australia
Segment Reporting Disclosure [Line Items]
Total revenues									34,868	44,801	70,669
Income (loss) before taxes									6,270	10,982	33,776
Total assets	149,534				172,406				149,534	172,406	182,155
Asia
Segment Reporting Disclosure [Line Items]
Total revenues									7,842	3,468	9,444
Income (loss) before taxes									323	(5,791)	(496)
Total assets	$ 4,678				$ 7,678				$ 4,678	$ 7,678	$ 11,785