Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Allowance for unfunded commitments	$ 2,600,000	$ 2,500,000
Data processing and communication charges	10,400,000	11,700,000	$ 9,800,000
Data processing, contract termination and conversion cost expenses	$ 0	$ 1,300,000	$ 0