Significant Accounting Policies (Details Textual) - USD ($)			3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	May 01, 2024	May 03, 2016	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Significant Accounting Policies [Line Items]
Redeemable noncontrolling interest, changes in redemption value						$ 4,409,000		$ 1,498,000
Redeemable Noncontrolling Interest Currency Adjustments						(311,000)		452,000
Asset Impairment Charges			$ 21,008,000	$ 0		23,325,000	$ 0
Redeemable Noncontrolling Interest, Equity, Fair Value			57,193,000			57,193,000		62,886,000	$ 60,180,000
Net cash provided by (used in) operating activities						(31,729,000)	(14,450,000)
Payment for contingent consideration							89,126,000
Goodwill			843,180,000			843,180,000		835,935,000
Acquisition related costs			232,000	216,000		943,000	$ 693,000
Assets			1,729,724,000			1,729,724,000		1,698,892,000
Liabilities			1,850,471,000			$ 1,850,471,000		1,791,519,000
Effective tax rate (percent)						8.40%	42.50%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent						26.50%
Provisional tax expense								(26,674,000)
Deferred Tax Assets, Net			1,198,000			$ 1,198,000		1,556,000
Income Tax Expense (Benefit)			2,986,000	9,049,000		(3,367,000)	$ 17,659,000
Income Tax Expense (Benefit), Change							21,026,000
Redeemable noncontrolling interest, redemptions, value						(9,791,000)		(910,000)
Noncontrolling Interest, Increase from Business Combination						0		1,666,000
Common Class A
Significant Accounting Policies [Line Items]
Restricted stock grant date fair value								$ 3,353,939
Aggregate 2017 Step-up Transaction
Significant Accounting Policies [Line Items]
Noncontrolling Interest, Increase from Business Combination					$ 2,652,000
Minimum
Significant Accounting Policies [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions						400,000
Maximum
Significant Accounting Policies [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions						500,000
Wells Fargo Capital Finance, LLC
Significant Accounting Policies [Line Items]
Debt instrument, maturity date		May 03, 2021
Contingent Payment
Significant Accounting Policies [Line Items]
Change in contingent purchase price obligation			$ 11,003,000	$ (2,462,000)		$ 8,522,000	$ 12,152,000
Forecast | 6.50% Notes due 2024 | Wells Fargo Capital Finance, LLC
Significant Accounting Policies [Line Items]
Debt instrument, maturity date	May 01, 2024
Preferred Stock | Series 4 Convertible Preferred Stock
Significant Accounting Policies [Line Items]
Shares outstanding (shares)			95,000			95,000		95,000
Accounting Standards Update 2016-15
Significant Accounting Policies [Line Items]
Net cash provided by (used in) operating activities						$ (36,570,000)
Canada
Significant Accounting Policies [Line Items]
Effective tax rate (percent)						26.30%
Vesting over period [Member]
Significant Accounting Policies [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value			$ 14,320			$ 14,320
Acquisition Value in excess of Redemption Value [Member]
Significant Accounting Policies [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value			4,333			4,333
Termination, disability, or death [Member]
Significant Accounting Policies [Line Items]
Redeemable Noncontrolling Interest, Equity, Fair Value			38,540			38,540
Unidentified Reporting Unit [Member]
Significant Accounting Policies [Line Items]
Goodwill			$ 130,000,000			$ 130,000,000