Income Taxes (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2015
Income Taxes [Line Items]
U.S. federal statutory rate	35.00%
Effective income tax rate	30.30%	29.40%
Income before income taxes, domestic operations	$ 12,300,000	$ 11,600,000
Income before income taxes, foreign operations	30,700,000	19,400,000
Liabilities for uncertain income tax positions	37,700,000						$ 35,900,000
Cash paid for income taxes	8,900,000	$ 8,100,000
Prepaid tax payments	5,500,000						$ 11,600,000
New York City Department of Finance [Member]
Income Taxes [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	$ 26,000
California Franchise Tax Board [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination				2013	2012
Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination			2014	2013	2012
New York State Division of Taxation and Finance [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination				2013	2012	2011