Income Taxes - Net Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets:
Compensation and benefits	$ 38,445	$ 38,131
Depreciation and amortization	2,883	2,937
Unrealized loss on investments	2,322	2,168
Operating loss carryforwards	4,310	4,647
Capital loss carryforwards	789	748
Foreign tax credit carryforwards	6,206	4,102
Other financial accruals	168	93
Valuation allowances	(7,611)	(4,519)
Total deferred tax assets	47,512	48,307
Deferred tax liabilities:
Unrealized gain on investments	4,302	16,994
Depreciation and amortization	125	190
Cumulative translation adjustment	3,726	1,759
Intangible asset acquired, net of amortization	199	1,042
Repatriation of foreign earnings	545	0
Other financial accruals	348	383
Total deferred tax liabilities	9,245	20,368
Net deferred tax asset	$ 38,267	$ 27,939