New Accounting Pronouncements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Income tax effects from Tax Act	$ 19,997,000	$ 20,153,000
ASU 2018-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Adjustment against retained earnings for effect of change in federal corporate income tax rate	40,000
Adjustments related to valuation allowance	0
Income tax effects from Tax Act	$ 0
ASU 2016-02 | Minimum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Percentage of right-of-use assets and liabilities expected to be recognized upon adoption of ASU	1.50%
ASU 2016-02 | Maximum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Percentage of right-of-use assets and liabilities expected to be recognized upon adoption of ASU	2.50%
ASU 2016-16
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Favorable adjustment to retained earnings	$ 31,645,000