Commitments and Contingencies - Additional Information (Details) shares in Thousands, ¥ in Billions			2 Months Ended		3 Months Ended	6 Months Ended
	Jul. 26, 2019 USD ($)	Jun. 30, 2019 USD ($)	May 03, 2019 USD ($)	Mar. 02, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2019 JPY (¥)	Jun. 24, 2016 USD ($)	Jul. 31, 2015 USD ($) shares
Other Commitments [Line Items]
Unfunded Commitments for Capital Contributions		$ 12,418,000				$ 12,418,000
Cash Paid For Contingent Consideration						2,008,000
Business Combination, Contingent Consideration, Liability		313,000				313,000
Asset Acquisition Contingent Consideration Liability		4,463,000				4,463,000
Asset Acquisition Contingent Consideration Arrangements Change In Amounts Of Contingent Consideration Liability					$ 1,033,000		$ (1,033,000)
Underwritten Shares (in shares) | shares											293
Aggregate Offering Price											$ 30,800,000
Foreign Exchange Forward [Member]
Other Commitments [Line Items]
Derivative Asset, Notional Amount								$ 35,598,000	¥ 3.8
BBVA Bancomer [Member]
Other Commitments [Line Items]
Maximum Borrowing Capacity		$ 7,800,000				$ 7,800,000
Secured Line of Credit [Member] | PNC Bank [Member]
Other Commitments [Line Items]
Maximum Borrowing Capacity										$ 30,000,000
Amount Outstanding During Period			$ 30,000,000	$ 30,000,000
Inter-Bank Balance Interest Rate [Member] | BBVA Bancomer [Member]
Other Commitments [Line Items]
Debt Instrument, Basis Spread on Variable Rate						0.10%
London Interbank Offered Rate (LIBOR) [Member] | Secured Line of Credit [Member] | PNC Bank [Member]
Other Commitments [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Subsequent Event [Member] | Unsecured Line of Credit [Member] | PNC Bank [Member]
Other Commitments [Line Items]
Maximum Borrowing Capacity	$ 20,000,000
Subsequent Event [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Line of Credit [Member] | PNC Bank [Member]
Other Commitments [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%