Pension and Employee Benefit Plans - Narrative (Details) - USD ($)	3 Months Ended	10 Months Ended	12 Months Ended			23 Months Ended
	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 28, 2018
Defined Benefit Plan Disclosure [Line Items]
Employer match of employee contributions (percent)	50.00%	100.00%				70.00%
Employer matching contribution maximum percent of employee's eligible compensation (percent)	5.00%	5.00%				5.00%
Duration of service period to receive matching contribution			1 year
Vesting period of benefits			3 years
Compensation expense related to 401(k) Plan			$ 4,730,000	$ 2,660,000	$ 2,280,000
Employer matching contributions related to deferred compensation plan			119,000	35,000	26,000
Employer discretionary contributions			0	$ 0	$ 0
Modified Retirement Plan | Unfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Estimated net loss to be amortized in next fiscal year		$ 59,000	59,000
Estimated prior service costs to be amortized in next fiscal year		635,000	635,000
Expected contribution to plan in year 2018		$ 1,142,000	$ 1,142,000
Funded Plan | Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for disclosures, retirees (percent)		3.60%	3.60%
Discount rate for disclosures, nonretirees, years 1 through 5 (percent)		3.33%	3.33%
Discount rate for disclosures, nonretirees, next 15 years (percent)		4.39%	4.39%
Discount rate assessment, nonretirees, next 15 years, period			15 years
Discount rate for disclosures, nonretirees, beyond 20 years (percent)		4.72%	4.72%
Estimated net loss to be amortized in next fiscal year		$ 0	$ 0
Estimated prior service costs to be amortized in next fiscal year		0	0
Expected contribution to plan in year 2018		$ 0	$ 0
Maximum | Funded Plan | Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate assessment, nonretirees, years 1 through 5, period			5 years
Minimum | Funded Plan | Funded Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate assessment, nonretirees, beyond 20 years period			20 years