Shareholders' Equity, Noncontrolling Interests and Other Comprehensive Income - Share Repurchases - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Stockholders Equity Including Portion Attributable To Noncontrolling Interest [Abstract]
Authorized amount			$ 200,000,000
Number of shares repurchased during period (in shares)	0		2,294,235
Shares repurchased during period		$ 31,961,000	$ 55,100,000
Stock repurchase fees			$ 100,000
Remaining authorized repurchase amount	$ 144,900,000