Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	2 Months Ended	3 Months Ended
	Mar. 10, 2017	Mar. 02, 2018	Mar. 31, 2018	Mar. 31, 2017	Jun. 24, 2016
Other Commitments [Line Items]
Rental Expense Relating to Operating Leases			$ 10,117,000	$ 9,517,000
Unfunded Commitments for Capital Contributions			$ 3,206,000
Inter-Bank Balance Interest Rate [Member]
Other Commitments [Line Items]
Debt Instrument, Basis Spread on Variable Rate			0.10%
PNC Bank [Member]
Other Commitments [Line Items]
Maximum Borrowing Capacity					$ 30,000,000
Amount Outstanding During Period	$ 30,000,000	$ 30,000,000
BBVA Bancomer [Member]
Other Commitments [Line Items]
Maximum Borrowing Capacity			$ 10,998,000